fix: root-anchor mcables ignore pattern, commit cmd/mcables/main.go

The bare `mcables` pattern in .gitignore (line 11) and .dockerignore
(line 18) was intended to ignore the built binary at the repo root, but
without a leading slash it also matched the cmd/mcables/ directory. The
result: cmd/mcables/main.go was never tracked in git, and fresh worktrees
had to copy it from a sibling to build.

- Change `mcables` → `/mcables` in both files (still ignores the root
  binary; no longer matches the cmd subdirectory).
- Add cmd/mcables/main.go (copied from picasso's worktree, verified
  identical to head's main checkout).

Verified: `git check-ignore cmd/mcables/main.go` returns not-ignored;
a touched `./mcables` at the repo root is still ignored via `/mcables`.
`go build ./...` clean.

.dockerignore

@@ -15,7 +15,7 @@ data
 
 # Build artefacts
 bin
-mcables
+/mcables
 
 # Editor cruft
 .vscode

.gitignore

@@ -8,7 +8,7 @@ data/*.db-shm
 
 # Build artefacts
 bin/
-mcables
+/mcables
 
 # Editor
 .vscode/

cmd/mcables/main.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"log"
+	"net/http"
+	"os"
+	"os/signal"
+	"path/filepath"
+	"syscall"
+	"time"
+
+	"mgit.msbls.de/m/mcables/internal/db"
+	"mgit.msbls.de/m/mcables/internal/server"
+	"mgit.msbls.de/m/mcables/web"
+)
+
+func main() {
+	addr := envOr("MCABLES_ADDR", "0.0.0.0:7777")
+	dbPath := envOr("MCABLES_DB", "./data/mcables.db")
+
+	if err := os.MkdirAll(filepath.Dir(dbPath), 0o755); err != nil {
+		log.Fatalf("mkdir data dir: %v", err)
+	}
+
+	store, err := db.Open(dbPath)
+	if err != nil {
+		log.Fatalf("open db: %v", err)
+	}
+	defer store.Close()
+
+	if err := db.Migrate(store.DB()); err != nil {
+		log.Fatalf("migrate: %v", err)
+	}
+
+	srv := &http.Server{
+		Addr:              addr,
+		Handler:           server.New(store, web.Static()),
+		ReadHeaderTimeout: 5 * time.Second,
+	}
+
+	go func() {
+		log.Printf("mcables listening on %s (db=%s)", addr, dbPath)
+		if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
+			log.Fatalf("listen: %v", err)
+		}
+	}()
+
+	stop := make(chan os.Signal, 1)
+	signal.Notify(stop, os.Interrupt, syscall.SIGTERM)
+	<-stop
+	log.Printf("shutting down")
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+	_ = srv.Shutdown(ctx)
+}
+
+func envOr(key, fallback string) string {
+	if v := os.Getenv(key); v != "" {
+		return v
+	}
+	return fallback
+}

docs/design.md

@@ -1438,4 +1438,228 @@ gitignored.
 
 ---
 
-DESIGN v4.1 READY FOR REVIEW
+## 11. v5 — Cable routing via clamps
+
+m's bundling primitive: a **clamp** is a physical anchor on the canvas
+(think cable tie / clip). A cable routes from its `from` endpoint,
+through zero or more clamps **in order**, to its `to` endpoint. Two
+cables that share an ordered pair of consecutive clamps are visibly
+bundled along that segment — no detection pass, no inference: the
+overlap *is* the bundle.
+
+This replaces the abandoned waypoints + segment-detection approach.
+v0's straight-line schematic stays as the empty-clamps case
+(`cable_clamps` is empty for a fresh solver-emitted cable).
+
+### 11.1 Schema (migration 007)
+
+```sql
+CREATE TABLE clamps (
+    id              INTEGER PRIMARY KEY,
+    project_id      INTEGER NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
+    x               REAL NOT NULL,
+    y               REAL NOT NULL,
+    label           TEXT NOT NULL DEFAULT '',
+    frame_id        INTEGER REFERENCES frames(id) ON DELETE SET NULL,
+    excalidraw_id   TEXT,
+    created_at      TEXT NOT NULL DEFAULT (datetime('now')),
+    updated_at      TEXT NOT NULL DEFAULT (datetime('now')),
+    UNIQUE (project_id, excalidraw_id)
+);
+CREATE INDEX clamps_project_idx ON clamps(project_id);
+
+CREATE TABLE cable_clamps (
+    cable_id        INTEGER NOT NULL REFERENCES cables(id) ON DELETE CASCADE,
+    clamp_id        INTEGER NOT NULL REFERENCES clamps(id) ON DELETE CASCADE,
+    ord             INTEGER NOT NULL,    -- 1..N along from→to
+    PRIMARY KEY (cable_id, ord),
+    UNIQUE (cable_id, clamp_id)          -- a cable can't visit the same clamp twice
+);
+CREATE INDEX cable_clamps_clamp_idx ON cable_clamps(clamp_id);
+```
+
+`frame_id` on clamps mirrors devices + IO markers — m can put a clamp
+inside a frame and the frame-drag carries it.
+
+`UNIQUE (cable_id, clamp_id)` blocks loops. `ord` is a small int, 1-based;
+nothing requires it to be contiguous (m can renumber 1, 2, 3 → 1, 3, 5
+during edits and the renderer is fine with that), but the UI keeps them
+contiguous on every mutation for sanity.
+
+### 11.2 Cable rendering model
+
+Each cable resolves to a polyline `[from-anchor, clamp₁, clamp₂, …, clampₙ, to-anchor]`
+where:
+- `from-anchor` / `to-anchor` come from the existing `anchorForEndpoint`
+  resolver (port / device / IO).
+- clamp anchors are `(clamp.x, clamp.y)` directly — clamps don't have a
+  width/height to centre.
+
+For N=0 clamps the result is the v0 straight line. For N≥1 we render
+a `<polyline>` instead of a `<line>`.
+
+The endpoint-replug handles from §10 (cable-replug) stay on the **first
+and last** vertices. Mid-polyline vertices get their own clamp-handle —
+small grab points only on the selected cable, which behave like
+clamp-detach when dragged onto empty canvas (drop a clamp off the
+cable's path).
+
+### 11.3 Bundle visualisation — derived from shared segments
+
+A **segment** is a directed pair `(A, B)` where A and B are consecutive
+nodes of a cable's polyline. Two cables share a segment when their
+polyline contains the same A→B (or B→A — segment matching is
+undirected).
+
+For each segment, compute `cables[]` — the cables that traverse it.
+If `len(cables) ≥ 2`, render the segment as a single thick line on top
+of the individual ones:
+
+- **Width**: `2 + N` px (N = cable count). Caps at ~12 px.
+- **Colour**: a striped pattern, one stripe per distinct cable type in
+  the bundle, ordered by cable_type.id. SVG `<linearGradient>` with
+  hard stops produces the stripe band cheaply; render it on a sibling
+  `<polyline>` over the individual lines.
+- **Tooltip**: `<title>` child listing the cables ("Power · USB · HDMI").
+
+At a clamp where ≥ 2 cables meet, the clamp icon (10×10 rounded square)
+shows a small count badge (`×N`) when N > 1. At fan-out points
+(endpoint with no clamp before it on the polyline) the individual
+coloured lines re-emerge, so m sees which port each strand goes to.
+
+Shared-segment computation is O(C·N̄) where C = #cables and N̄ = average
+polyline length. For a v0-sized project (≤ ~30 cables, ≤ ~5 clamps per
+cable) this is trivial. We rebuild the segment map on every renderCanvas
+— no caching layer.
+
+### 11.4 UI gestures
+
+**+ Clamp tool (`C` shortcut, also a sidebar button):**
+- Click empty canvas → place a clamp at the cursor (POST `/clamps`).
+  Standalone clamp — not on any cable yet.
+- Click a cable line → insert this clamp into that cable. The new clamp
+  sits at the click position (snapped to the nearest point on the
+  cable's polyline) and its `ord` is computed so it falls between the
+  two existing vertices it lies between.
+
+**Drag a cable's mid-segment:**
+- Pointerdown on a cable line (not on an endpoint handle) and drag.
+  Live preview shows a bend at the cursor. Pointerup:
+  - If the cursor is within snap-radius (~16 px) of an existing clamp:
+    insert that clamp into the cable's polyline at the right `ord`.
+  - Otherwise: create a fresh clamp at the release point and insert it.
+
+**Clamp inspector** (selecting a clamp on the canvas):
+- Position (x, y editable + label)
+- "Cables through this clamp": list with each cable's two endpoints,
+  click → select that cable
+- "Remove from this cable" (per row) → DELETE the matching cable_clamps
+  row; cable's polyline collapses around the gap.
+- "Delete clamp" → cascade-removes from every cable_clamps row.
+
+**Right-click on a clamp icon ON a cable** → "Remove from this cable"
+inline.
+
+**Frame drag** carries clamps the same way it carries devices + IO
+markers (clamp.frame_id mirrors the existing pattern, drag handler
+already iterates frame-contained items).
+
+### 11.5 Relationship to the existing `bundles` table
+
+**Recommendation: keep `bundles` and `bundle_cables`, repurpose them.**
+
+- Implicit/auto bundles → derived live from shared clamp segments. No
+  DB rows. The §5 `GET /bundles/suggestions` endpoint stays useful as a
+  "you might want to route these through the same clamps" hint.
+- Explicit named bundles → still in the `bundles` table. m names a
+  group ("desk → wall trunk"), the UI offers "route all members through
+  these clamps" as a one-click action. Useful for the case where m
+  wants a stable label on a logical bundle that isn't yet routed.
+
+Migration 007 leaves `bundles` + `bundle_cables` untouched. A v6 cleanup
+can drop them if m decides the explicit-named path isn't worth keeping.
+
+### 11.6 Solver coupling
+
+The v0 solver still emits **straight cables** — no clamp rows. m
+hand-routes after Solve. The solver's preview-diff is unaffected
+(solver compares endpoint pairs; clamp routing is independent of the
+endpoint identity).
+
+Future v5.1: solver-suggested clamps based on shared paths between
+endpoint pairs. Out of scope here.
+
+### 11.7 Export to mxdrw
+
+Clamps map to small diamond elements (separate from IO markers — IO
+diamonds are red wall-outlets; clamps are grey routing points).
+`excalidraw_id` is stable across re-exports per the existing pattern.
+
+Cable arrows become Excalidraw `arrow` elements with mid-points (the
+clamp positions) when N≥1 — Excalidraw supports multi-vertex arrows
+via the `points` array. Each `startBinding` / `endBinding` resolves to
+the from/to anchor's excalidraw_id; mid-vertices are unbound.
+
+Bundle visualisation (thick striped lines on shared segments) is **not
+exported** in v0 — Excalidraw doesn't natively support gradient strokes,
+and the mxdrw round-trip would lose them. We export each cable as its
+own polyline; bundling is a viewer-only concept.
+
+### 11.8 API additions
+
+```
+POST   /api/projects/:pid/clamps                   { x, y, label?, frame_id? } → Clamp
+PATCH  /api/projects/:pid/clamps/:id               { x?, y?, label?, frame_id? } → Clamp
+DELETE /api/projects/:pid/clamps/:id
+
+POST   /api/projects/:pid/cables/:cid/clamps       { clamp_id, ord? } → CableClamp
+DELETE /api/projects/:pid/cables/:cid/clamps/:cmid
+
+# Convenience: re-order clamps on a cable in one call
+PUT    /api/projects/:pid/cables/:cid/clamps       { clamp_ids: [int, int, …] }
+```
+
+Snapshot endpoint grows two arrays:
+- `clamps: []Clamp`
+- `cable_clamps: []{ cable_id, clamp_id, ord }`
+
+### 11.9 Open questions for m
+
+1. **Clamp icon shape.** Diamond (overlaps visually with IO markers
+   when zoomed out), small filled circle (overlaps with port circles),
+   or rounded square `▢` 10×10? Recommend rounded square — distinct from
+   everything else on the canvas today.
+2. **Snap radius when inserting onto a cable.** ~16 px world-units feels
+   right at 1× zoom. Should it scale with zoom (visual constant) or stay
+   world-constant (gesture stays the same regardless of zoom)? Recommend
+   visual constant — divide by current zoom.
+3. **Clamp deletion when shared.** If a clamp is used by 4 cables and m
+   clicks "Delete clamp", do we (a) refuse with a "still in use" prompt,
+   (b) cascade-remove from all 4 cables, or (c) cascade silently? Current
+   draft says cascade silently. Worth a confirmation?
+4. **Bundle stripe order.** Cable-type id is stable but arbitrary; visual
+   order on a thick line affects readability. Order by stripe-count
+   (Power first if 3 Power + 1 USB), or by cable-type-id (deterministic
+   but unrelated to importance)? Recommend by-count, ties broken by id.
+5. **Solver respect for existing routing.** When m re-runs Solve after
+   hand-routing, should the solver preserve existing clamp routing on
+   user-owned (`auto=0`) cables? Auto cables are wiped + rebuilt, so
+   their clamps disappear with them — that's expected. But manual cables
+   with clamps should clearly keep them. Confirm.
+
+### 11.10 Slice plan (post-design)
+
+1. Schema migration + tx-aware store helpers (Create/Update/DeleteClamp,
+   AttachClampToCable, DetachClampFromCable, ReorderClamps).
+2. HTTP endpoints + snapshot extension.
+3. Frontend: clamp render + + Clamp tool + canvas placement (no
+   cable attach yet).
+4. Cable polyline render via clamps, mid-segment drag-to-clamp,
+   clamp inspector.
+5. Shared-segment bundle visualisation (gradient stripe + count badge).
+6. Export pipeline extension — mxdrw arrows with mid-points + clamp
+   diamonds. Bundle viz stays viewer-only.
+
+---
+
+DESIGN v5 READY FOR REVIEW

web/static/main.js

@@ -471,6 +471,18 @@ function renderCanvas() {
       });
       // Port-click drives both cable-draw (slice 7) and port-select (this fix).
       c.addEventListener("pointerdown", (e) => onPortPointerDown(e, prt));
+      // Double-click activates cable-draw mode from this port without arming
+      // the cable tool first. armTool("cable") gives the crosshair cursor;
+      // the next port-click is then caught by onPortPointerDown's
+      // cable-draw-in-progress branch and commits the cable.
+      c.addEventListener("dblclick", (e) => {
+        e.stopPropagation();
+        e.preventDefault();
+        if (state.tool !== "cable") armTool("cable");
+        state.cableDrawFromPortID = prt.id;
+        state.selection = null;
+        render();
+      });
       g.append(c);
     }
 
@@ -534,14 +546,22 @@ function renderCanvas() {
   const deviceByID = new Map(state.devices.map((d) => [d.id, d]));
   const ioByID = new Map(state.ioMarkers.map((m) => [m.id, m]));
   for (const c of state.cables) {
-    const fromAnchor = anchorForEndpoint(c.from_port_id, c.from_device_id, c.from_io_id, portByID, deviceByID, ioByID);
-    const toAnchor   = anchorForEndpoint(c.to_port_id,   c.to_device_id,   c.to_io_id,   portByID, deviceByID, ioByID);
+    let fromAnchor = anchorForEndpoint(c.from_port_id, c.from_device_id, c.from_io_id, portByID, deviceByID, ioByID);
+    let toAnchor   = anchorForEndpoint(c.to_port_id,   c.to_device_id,   c.to_io_id,   portByID, deviceByID, ioByID);
     if (!fromAnchor || !toAnchor) continue;
+    // Replug preview: while m drags an endpoint handle, override the
+    // affected end with the live cursor world position so the line
+    // tracks the pointer.
+    if (cableReplug && cableReplug.cableID === c.id) {
+      if (cableReplug.end === "from") fromAnchor = { x: cableReplug.x, y: cableReplug.y };
+      else                            toAnchor   = { x: cableReplug.x, y: cableReplug.y };
+    }
+    const isSelected = state.selection?.kind === "cable" && state.selection.id === c.id;
     const color = cableTypeColor.get(c.type_id) || "#888";
     const line = svgEl("line", {
       x1: fromAnchor.x, y1: fromAnchor.y,
       x2: toAnchor.x,   y2: toAnchor.y,
-      class: "cable-line" + (c.auto ? " auto" : "") + (state.selection?.kind === "cable" && state.selection.id === c.id ? " selected" : ""),
+      class: "cable-line" + (c.auto ? " auto" : "") + (isSelected ? " selected" : ""),
       stroke: color,
       "data-cable-id": c.id,
     });
@@ -551,6 +571,23 @@ function renderCanvas() {
       render();
     });
     gCables.append(line);
+    // Endpoint handles — only on the currently-selected cable. Two small
+    // filled circles m can grab to drag the endpoint onto a new target.
+    if (isSelected) {
+      for (const end of ["from", "to"]) {
+        const a = end === "from" ? fromAnchor : toAnchor;
+        const h = svgEl("circle", {
+          cx: a.x, cy: a.y, r: 7,
+          class: "cable-handle",
+          fill: color,
+          stroke: "#fff",
+          "data-cable-id": c.id,
+          "data-end": end,
+        });
+        h.addEventListener("pointerdown", (e) => startCableReplug(e, c.id, end));
+        gCables.append(h);
+      }
+    }
   }
 }
 
@@ -1638,6 +1675,10 @@ function bindTools() {
 
 let rubberBand = /** @type {SVGRectElement|null} */ (null);
 let rubberStart = /** @type {{x:number,y:number}|null} */ (null);
+// Live state for a cable-endpoint replug drag. Captured at pointerdown
+// on a .cable-handle, used by renderCanvas to anchor the dragged end
+// at the cursor; cleared on pointerup (commit or cancel).
+let cableReplug = /** @type {{cableID: number, end: "from"|"to", x: number, y: number}|null} */ (null);
 
 function onCanvasPointerDown(e) {
   // Pan gestures win over every tool. Middle-click and Space+drag both
@@ -1975,6 +2016,95 @@ function startResize(e, deviceID) {
   svg.addEventListener("pointercancel", onUp);
 }
 
+// Find the topmost canvas element under (clientX, clientY) that maps to
+// a cable endpoint target. Returns { kind, id } for port / device / IO,
+// or null when m dropped on empty canvas.
+function hitTestEndpointTarget(clientX, clientY) {
+  // elementsFromPoint walks the z-order so we can skip the dragged
+  // cable handle itself (it sits at the top while pointer-captured).
+  const els = document.elementsFromPoint(clientX, clientY);
+  for (const el of els) {
+    if (!(el instanceof Element)) continue;
+    if (el.classList?.contains("cable-handle")) continue; // skip self
+    const portID = el.getAttribute && el.getAttribute("data-port-id");
+    if (portID) return { kind: "port", id: Number(portID) };
+    const devEl = el.closest && el.closest("[data-device-id]");
+    if (devEl) return { kind: "device", id: Number(devEl.getAttribute("data-device-id")) };
+    const ioEl = el.closest && el.closest("[data-io-id]");
+    if (ioEl) return { kind: "io", id: Number(ioEl.getAttribute("data-io-id")) };
+  }
+  return null;
+}
+
+// Endpoint-drag gesture: pointerdown on a .cable-handle starts a replug.
+// While held, renderCanvas anchors the affected end at the cursor.
+// On pointerup, hit-test the cursor to find the drop target:
+//   - port  → PATCH {from|to: {port_id}}
+//   - device → PATCH {from|to: {device_id}}
+//   - IO    → PATCH {from|to: {io_id}}
+//   - empty → cancel (revert)
+// When the cable was auto, a successful drop also sends promote=true so
+// the server flips it to manual (m took control). Cancel leaves auto alone.
+function startCableReplug(e, cableID, end) {
+  if (!state.active) return;
+  e.stopPropagation();
+  e.preventDefault();
+  const c = state.cables.find((x) => x.id === cableID);
+  if (!c) return;
+  const svg = /** @type {SVGSVGElement} */ ($("#canvas"));
+  try { svg.setPointerCapture(e.pointerId); } catch {}
+  $(".canvas-wrap").classList.add("replugging");
+  const startWorld = svgPoint(e);
+  cableReplug = { cableID, end, x: startWorld.x, y: startWorld.y };
+  renderCanvas();
+
+  const onMove = (ev) => {
+    const p = svgPoint(ev);
+    cableReplug = { cableID, end, x: p.x, y: p.y };
+    renderCanvas();
+  };
+  const onUp = async (ev) => {
+    svg.removeEventListener("pointermove", onMove);
+    svg.removeEventListener("pointerup",   onUp);
+    svg.removeEventListener("pointercancel", onUp);
+    try { svg.releasePointerCapture(ev.pointerId); } catch {}
+    $(".canvas-wrap").classList.remove("replugging");
+    const drop = hitTestEndpointTarget(ev.clientX, ev.clientY);
+    // Clear the preview first so renderCanvas falls back to resolved anchors.
+    cableReplug = null;
+    if (!drop) {
+      renderCanvas();
+      return; // cancel
+    }
+    // Build the patch for the affected endpoint.
+    const ep =
+      drop.kind === "port"   ? { port_id:   drop.id } :
+      drop.kind === "device" ? { device_id: drop.id } :
+      drop.kind === "io"     ? { io_id:     drop.id } : null;
+    if (!ep) { renderCanvas(); return; }
+    const body = {};
+    if (end === "from") body.from = ep; else body.to = ep;
+    if (c.auto) body.promote = true;
+    // If m dropped on the same endpoint we already had, treat as cancel.
+    const sameAsBefore =
+      (drop.kind === "port"   && ((end === "from" ? c.from_port_id   : c.to_port_id)   === drop.id)) ||
+      (drop.kind === "device" && ((end === "from" ? c.from_device_id : c.to_device_id) === drop.id)) ||
+      (drop.kind === "io"     && ((end === "from" ? c.from_io_id     : c.to_io_id)     === drop.id));
+    if (sameAsBefore) { renderCanvas(); return; }
+    try {
+      const updated = await patchCable(state.active.id, c.id, body);
+      Object.assign(c, updated);
+      render();
+    } catch (err) {
+      alert(`Replug failed: ${err.message}`);
+      renderCanvas();
+    }
+  };
+  svg.addEventListener("pointermove", onMove);
+  svg.addEventListener("pointerup",   onUp);
+  svg.addEventListener("pointercancel", onUp);
+}
+
 /** Port-click flow:
  *  - A cable draw is in progress (cableDrawFromPortID set):
  *     same port → cancel; another port → finish the cable.

web/static/style.css

@@ -407,6 +407,17 @@ body {
 .cable-line:hover { stroke-width: 4; }
 .cable-line.selected { stroke-width: 4; }
 
+/* Endpoint handles — only rendered for the currently-selected cable.
+   Grab cursor on idle, grabbing while dragging (.replugging on root). */
+.cable-handle {
+  cursor: grab;
+  stroke-width: 2;
+  filter: drop-shadow(0 0 2px rgba(0, 0, 0, 0.35));
+}
+.cable-handle:hover { stroke-width: 3; }
+.canvas-wrap.replugging .cable-handle,
+.canvas-wrap.replugging #canvas * { cursor: grabbing !important; }
+
 /* Solve preview-diff modal */
 .modal-wide { width: 560px; }