fix(litigationplanner): respect trigger_event_id + suppress optional from default (yoUPC#178 + #2568/#2570)

Two paired engine semantics fixes:

1. trigger_event_id is now the authoritative semantic anchor. When a
   rule carries trigger_event_id, the engine no longer falls back to
   the proceeding's trigger date — it resolves the anchor via
   CalcOptions.TriggerEventAnchors keyed by paliad.trigger_events.code.
   Missing anchor renders the rule as IsConditional (empty date) and
   propagates via courtSet so descendants also surface as conditional.
   Fixes the RoP.109.5 bug where the engine fabricated a date 2 weeks
   before the user's SoC instead of waiting for the oral_hearing date.

2. priority='optional' rules are suppressed from the default
   Calculate output. Callers (paliad /tools/procedures,
   youpc.org/deadlines) opt in via CalcOptions.IncludeOptional=true to
   restore the legacy "show optional applications" behaviour. The
   suppression cascades through skippedIDs so child rules drop too.

Wire shape additions:

  - CalcOptions.IncludeOptional bool
  - CalcOptions.TriggerEventAnchors map[string]string
  - Timeline.RulesAwaitingAnchor int (count of suppressed-by-missing-
    anchor rules, for caller telemetry / "N rules need an anchor" UX)

Existing before-court-set-anchor tests opt in to IncludeOptional=true
to preserve their non-optional-related test intent.

Refs: youpcorg/head delegations #2568 + #2570, m/paliad#153 (Litigation
Builder PRD path).

pkg/litigationplanner/types.go

@@ -334,6 +334,25 @@ type CalcOptions struct {
 	// filter applied) so a stale frontend chip doesn't break the
 	// timeline render — see IsValidAppealTarget.
 	AppealTarget string
+
+	// IncludeOptional surfaces rules with priority='optional' in the
+	// default timeline (t-paliad-342 / youpcorg#2570). Default false:
+	// optional rules don't auto-fire alongside mandatory ones. The
+	// caller (paliad /tools/procedures, youpc.org/deadlines) wires this
+	// to a user-facing "show optional applications" toggle.
+	IncludeOptional bool
+
+	// TriggerEventAnchors supplies concrete dates for procedural events
+	// referenced by rules' trigger_event_id (t-paliad-342 / youpcorg#2568).
+	// Key = paliad.trigger_events.code (e.g. "oral_hearing"), value =
+	// YYYY-MM-DD. When a rule carries an explicit trigger_event_id, that
+	// catalog event is the authoritative semantic anchor: arithmetic
+	// resolves against TriggerEventAnchors[code] if set, otherwise the
+	// rule is suppressed as IsConditional (no fabricated date off the
+	// user's trigger date). Empty map = engine never anchors on a
+	// trigger event, so every rule with trigger_event_id surfaces as
+	// conditional.
+	TriggerEventAnchors map[string]string
 }
 
 // ProjectHint scopes a Catalog call to a specific project. Paliad's
@@ -375,6 +394,13 @@ type Timeline struct {
 	TriggerEventLabel   string          `json:"triggerEventLabel,omitempty"`
 	TriggerEventLabelEN string          `json:"triggerEventLabelEN,omitempty"`
 	HiddenCount         int             `json:"hiddenCount"`
+	// RulesAwaitingAnchor counts rules suppressed because their
+	// trigger_event_id anchor date wasn't supplied via
+	// CalcOptions.TriggerEventAnchors (t-paliad-342). Such rules still
+	// render in the timeline as IsConditional (no date) — the field
+	// gives the caller a single integer for "N rules waiting on an
+	// anchor" UI affordances + telemetry.
+	RulesAwaitingAnchor int `json:"rulesAwaitingAnchor,omitempty"`
 }
 
 // TimelineEntry matches the frontend's CalculatedDeadline TypeScript