rename: mCables → CableGUI (project + repo + image + paths)

Full project rename per m's call. Single atomic commit because the
codebase rename is a coupled change — go module path, env vars, DB
default, Docker artefact names, and on-disk mDock paths all flip
together.

- go.mod: module mgit.msbls.de/m/mcables → mgit.msbls.de/m/cablegui
- cmd/mcables → cmd/cablegui (git mv)
- All Go imports rewritten to the new module path
- Env vars: MCABLES_ADDR/MCABLES_DB → CABLEGUI_ADDR/CABLEGUI_DB
- DB default path: data/mcables.db → data/cablegui.db
- Dockerfile + docker-compose.yml: image, container_name, env vars,
  bind-mount /home/m/stacks/mcables → /home/m/stacks/cablegui,
  secrets /home/m/secrets/mcables → /home/m/secrets/cablegui
- Makefile: bin target + run/build commands point at cmd/cablegui
- .gitignore + .dockerignore: /mcables → /cablegui
- README, docs/design.md, CLAUDE.md: prose + paths + image name
- web/static/index.html: <title> + brand
- web/static/main.js + web/web.go: header comment
- internal/exporter: Scene.Source "mcables" → "cablegui"
- internal/server/export.go: error-detail secrets path
- internal/db/migrations/*.sql: header comments (mCables vN → CableGUI vN)

Memory group_id kept as "mcables" to preserve existing memory continuity.
Documented as historical in CLAUDE.md.

go build ./... clean; go test -race ./... green

CLAUDE.md

@@ -1,11 +1,11 @@
-# mCables — Project Instructions
+# CableGUI — Project Instructions
 
 ## Project Overview
 
 Cable-management **framework + solver** for m's setup. m declares his
 **devices** and the **connection requirements** between them ("NAS must
-connect to Switch via RJ45"). mCables runs a solver that emits the cable
-plan + bundle recommendations. mCables is a **schematic**, not a
+connect to Switch via RJ45"). CableGUI runs a solver that emits the cable
+plan + bundle recommendations. CableGUI is a **schematic**, not a
 physical-routing tool — cables are straight lines between endpoints; the
 "maximum bundling" objective is satisfied by the endpoint-pair rule
 (when two or more cables share the same A↔B endpoint pair, group them
@@ -13,16 +13,17 @@ into one bundle). The visual editor is still there for tweaking the
 plan, but the solver is the headline.
 
 Each cable-managed environment (LOFT, OFFICE, …) is a separate
-**mCables project**, and each project is backed by exactly one Excalidraw
+**CableGUI project**, and each project is backed by exactly one Excalidraw
 drawing. The framework provides a visual web interface backed by a Go
 HTTP API and SQLite, plus an export pipeline that writes `.excalidraw`
 files via mExDraw.
 
-**Memory group_id:** `mcables`
+**Memory group_id:** `mcables` (kept historical — all prior memories live
+under this id; renaming would orphan them)
 
 **No CLI.** Frontend-first — every interaction is through the visual
 interface. The backend serves the UI and the API; there is no
-`mcables` shell binary intended for humans.
+`cablegui` shell binary intended for humans.
 
 ## Goal
 
@@ -53,7 +54,7 @@ interface. The backend serves the UI and the API; there is no
 
 | Layer | Tech | Notes |
 |---|---|---|
-| DB | SQLite | `./data/mcables.db` (project-local, gitignored). Driver: `modernc.org/sqlite` (cgo-free). |
+| DB | SQLite | `./data/cablegui.db` (project-local, gitignored). Driver: `modernc.org/sqlite` (cgo-free). |
 | Backend | Go | `net/http` HTTP API + static frontend via `embed.FS`. Standard library + minimal deps. Single binary. |
 | Frontend | Vanilla JS modules + SVG, no build step | TypeScript types via JSDoc, optional `tsc --noEmit` in CI. Preact-via-CDN-ESM is the documented fallback if vanilla state gets painful — no build step either way. |
 | Diagram I/O | mExDraw HTTP API | `PUT https://mxdrw.msbls.de/api/drawings/<name>.excalidraw` with `Authorization: Bearer $MEXDRAW_TOKEN`. (The `mcp__mexdraw__*` MCP tools are not currently configured for this project — workers use the raw HTTP API.) |
@@ -112,14 +113,14 @@ interface. The backend serves the UI and the API; there is no
 
 ## Deployment — mDock, raw docker (NOT Dokploy)
 
-mCables runs on **mDock** (`192.168.178.131` on the LAN, Tailscale `mdock`)
+CableGUI runs on **mDock** (`192.168.178.131` on the LAN, Tailscale `mdock`)
 as a **plain docker-compose service**. Dokploy is for public mlake/mRiver
 stuff; mDock uses raw `docker compose` per the conventions of the existing
 mDock services (mgreen, mgeo, msports-garmin, paperless, …).
 
-- Repo layout on mDock: `/home/m/stacks/mcables/` with `docker-compose.yml`,
-  `data/` bind-mount, secrets in `/home/m/secrets/mcables/.env`.
-- Image: `mgit.msbls.de/m/mcables:latest` (built and pushed by a Gitea
+- Repo layout on mDock: `/home/m/stacks/cablegui/` with `docker-compose.yml`,
+  `data/` bind-mount, secrets in `/home/m/secrets/cablegui/.env`.
+- Image: `mgit.msbls.de/m/cablegui:latest` (built and pushed by a Gitea
   Actions workflow on push to `main`, runs on the self-hosted runner on
   mDock with label `self-hosted:host`).
 - Port mapping: `7777:7777`, exposed on the LAN — no reverse proxy.
@@ -127,12 +128,12 @@ mDock services (mgreen, mgeo, msports-garmin, paperless, …).
 - LAN URL: `http://mdock:7777`.
 - No auth — LAN-trusted.
 
-Local dev (no Docker): `go run ./cmd/mcables` against `./data/mcables.db`.
+Local dev (no Docker): `go run ./cmd/cablegui` against `./data/cablegui.db`.
 
 ## Seed drawing — visual grammar reference, **not** a runtime importer
 
 `mxdrw.msbls.de/draw/Cable-Management.excalidraw` is **reference material
-only**. mCables does **not** auto-ingest it. m will rebuild LOFT and OFFICE
+only**. CableGUI does **not** auto-ingest it. m will rebuild LOFT and OFFICE
 from scratch inside the tool — the seed exists so the **exporter** mimics
 its visual grammar:
 
@@ -163,13 +164,13 @@ Legend colours (global, seeded once by migration 001):
 
 ## Out of scope (v0)
 
-- Multi-user. mCables is m-only.
+- Multi-user. CableGUI is m-only.
 - Auth / sharing — LAN-trusted on mDock.
 - Mobile / responsive — desktop browser only.
 - Cable inventory beyond visual structure (no length, no purchase history,
   no SKU). Strictly visual structure for v0.
 - Import from `.excalidraw` at runtime. If a one-shot migration is ever
-  needed, a separate `mcables-migrate` CLI tool is the right shape, not a
+  needed, a separate `cablegui-migrate` CLI tool is the right shape, not a
   hot API endpoint.
 
 ## Worker Preferences