feat(graph): continual-learning graph data model + dark-Bauhaus viz

Adds the team_model graph layer (the "it learned" view) and its visualization,
per docs/graph.md. Demo-backed first; built on origin/main conventions.

- shared: PodGraph / node / edge / metric types + GraphNodeDoc / GraphEdgeDoc
- backend/src/graph: demo graph data; Mongo store (loadPodGraph w/ demo
  fallback, seedGraph, reachFrom via $graphLookup); graph:seed script
- backend/src/server.ts: additive GET /api/pods/:id/graph + /graph/reach/:node
- frontend: dark-Bauhaus GraphView + fetch helper, reachable from a
  "Team memory" toggle in App.tsx
- docs/graph.md: spec (data model, $graphLookup, API, demo-first plan)

Demo-backed: the route serves a grounded demo graph when team_model has no
graph yet; graph:seed writes team_model + graph_nodes/graph_edges so the
$graphLookup traversal is real. Swap loadPodGraph to live team_model later.

Known follow-ups before merge: branch is based on 65a0791; origin/main is now
at 1294b84, so this needs a rebase + App.tsx conflict resolution (teammate
rewrote App.tsx with live room view / one-click join).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

shared/src/graph.ts

@@ -0,0 +1,69 @@
+/**
+ * Continual-learning graph: PodMan's visible "it learned" surface. A render of
+ * the per-pod team_model — who owns/edits which files, where work collides, and
+ * what PodMan learned from accepted interventions (the `learned_from` edges).
+ *
+ * Served embedded in the `team_model` document; mirrored into `graph_nodes` /
+ * `graph_edges` collections so the model can be walked with MongoDB
+ * `$graphLookup`. See docs/graph.md.
+ */
+
+export type PodGraphNodeKind = 'engineer' | 'feature' | 'file' | 'collision' | 'intervention';
+
+export type PodGraphEdgeKind =
+  'owns' | 'editing' | 'touches' | 'collides' | 'warns' | 'learned_from';
+
+/** `learned` marks a node PodMan retained from a past accepted intervention. */
+export type PodGraphNodeStatus = 'stable' | 'active' | 'risk' | 'learned';
+
+export interface PodGraphNode {
+  /** Stable graph id, e.g. "engineer:karti" or "file:auth.ts". */
+  id: string;
+  kind: PodGraphNodeKind;
+  label: string;
+  summary: string;
+  /** 0–1 relative importance — drives node size in the viz. */
+  weight: number;
+  status: PodGraphNodeStatus;
+  /** Layout position on the SVG canvas (viewBox 0..720 x 0..472). */
+  x: number;
+  y: number;
+}
+
+export interface PodGraphEdge {
+  id: string;
+  /** Source node id. */
+  source: string;
+  /** Target node id. */
+  target: string;
+  kind: PodGraphEdgeKind;
+  label: string;
+  /** 0–1 confidence/strength — drives edge thickness. */
+  strength: number;
+}
+
+export interface PodGraphMetric {
+  label: string;
+  value: string;
+  detail: string;
+}
+
+/** A point-in-time render of a pod's team_model. */
+export interface PodGraph {
+  podId: string;
+  /** ISO timestamp the snapshot was generated. */
+  generatedAt: string;
+  nodes: PodGraphNode[];
+  edges: PodGraphEdge[];
+  metrics: PodGraphMetric[];
+}
+
+/** One node as a standalone document in the `graph_nodes` collection. */
+export interface GraphNodeDoc extends PodGraphNode {
+  podId: string;
+}
+
+/** One edge as a standalone document in the `graph_edges` collection (for $graphLookup). */
+export interface GraphEdgeDoc extends PodGraphEdge {
+  podId: string;
+}

shared/src/index.ts

@@ -9,3 +9,14 @@ export type {
   SuggestedActionKind,
 } from './intervention.js';
 export * from './messages.js';
+export type {
+  PodGraph,
+  PodGraphNode,
+  PodGraphEdge,
+  PodGraphMetric,
+  PodGraphNodeKind,
+  PodGraphEdgeKind,
+  PodGraphNodeStatus,
+  GraphNodeDoc,
+  GraphEdgeDoc,
+} from './graph.js';