feat(family): the promotion engine - triggers, the three criteria, the decision log and undo (milestone 463 step 3, #4989)

The agent promotes a family idea when all three criteria hold, and no person approves it. The criteria are product text: services/family.py states them, and the promote tool's docstring names every criterion the service enforces.

- Criteria: each one vetoes on its own when its reasoning is blank. Platform terms also needs an applies-when and a platform scope; proven also needs named evidence. A veto keeps the idea a candidate and is logged, so it becomes precedent.
- Precedent: every promotion stores the decisions on the nearest ideas by meaning, plus any the caller names.
- Promotion sets canon, the applicability test and the platform scope, and opens an unassessed ledger row for each member project the promoter can write. Re-promotion moves the version past every version the idea has held.
- Retire and undo: undo reverses only the latest idea-level decision, restores its recorded before-state, and logs itself with the undone decision as its precedent. Settled here: leaving canon closes the unassessed rows but keeps the judged ones, which read as needing a recheck after a re-promotion.
- Triggers open evaluations but never promote:
  - a cross-project lineage citation ("matching #N") on a note or task write;
  - a same-meaning record in another project on a shared platform, on create, at 0.80 (measured: the known pattern's builds scored 0.79-0.82, an unrelated project's best match 0.65);
  - a milestone closing on a platform.
  Each fails open and rides the response as family_hint.
- Doors: seven MCP tools, /api/family REST endpoints, and a Family page (nav, /family) showing the criteria, the ideas, and the decision log with undo and retire.
- utils/recordHref.ts holds the one copy of "where a record opens", now shared with LessonDetailView.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/api/family.ts

@@ -0,0 +1,78 @@
+/**
+ * Family canon (milestone 463): ideas every project on a platform shares, and
+ * the log of every decision about them.
+ *
+ * The agent promotes by written criteria — no approval step. This door is for
+ * reading what was decided and why, and for retiring an idea or undoing a
+ * decision when a person disagrees.
+ */
+import { apiGet, apiPost } from "@/api/client";
+
+export type IdeaStatus = "candidate" | "canon" | "retired";
+export type DecisionAction = "propose" | "promote" | "revise" | "retire" | "assess" | "undo";
+
+export interface Criterion {
+  key: string;
+  title: string;
+  test: string;
+}
+
+export interface FamilyIdea {
+  note_id: number;
+  status: IdeaStatus;
+  applies_when: string;
+  canon_version: number;
+  topic_id: number | null;
+  title: string;
+  note_type: string;
+  is_task: boolean;
+  project_id: number | null;
+  platforms: string[];
+  created_at: string | null;
+  updated_at: string | null;
+}
+
+/** A state snapshot a decision records — slugs, never ids. */
+export interface IdeaSnapshot {
+  status: IdeaStatus;
+  applies_when: string;
+  canon_version: number;
+  platforms: string[];
+}
+
+export interface FamilyDecision {
+  id: number;
+  idea_id: number;
+  idea_title?: string;
+  project_id: number | null;
+  action: DecisionAction;
+  reason: string;
+  before: IdeaSnapshot | null;
+  after: IdeaSnapshot | null;
+  evidence: Record<string, unknown>;
+  precedent_ids: number[];
+  decided_via: "agent" | "operator" | "system";
+  user_id: number | null;
+  created_at: string | null;
+  undoable?: boolean;
+}
+
+export async function listFamilyIdeas(status = ""): Promise<{ ideas: FamilyIdea[]; criteria: Criterion[] }> {
+  const q = status ? `?status=${encodeURIComponent(status)}` : "";
+  return apiGet(`/api/family/ideas${q}`);
+}
+
+export async function listFamilyDecisions(limit = 50, offset = 0): Promise<FamilyDecision[]> {
+  const data = await apiGet<{ decisions: FamilyDecision[] }>(
+    `/api/family/decisions?limit=${limit}&offset=${offset}`,
+  );
+  return data.decisions;
+}
+
+export async function undoFamilyDecision(id: number, reason: string) {
+  return apiPost<{ decision: FamilyDecision }>(`/api/family/decisions/${id}/undo`, { reason });
+}
+
+export async function retireFamilyIdea(noteId: number, reason: string) {
+  return apiPost<{ decision: FamilyDecision }>(`/api/family/ideas/${noteId}/retire`, { reason });
+}