feat(graph): dynamic force-directed Team-memory graph + learning-loop & activity rails

Rebuild the live "Team memory" view so the light/real-data version matches the
dark Bauhaus mock and the graph is genuinely DYNAMIC instead of dead static columns.

Frontend (frontend/src/components/graph/*, composed into GraphView.tsx):
- forceSim.ts: a tiny dependency-free force layout (charge repulsion, link springs,
  centroid recentering + gentle pull, 2-pass collision, bounds clamp, alpha anneal).
  No d3-force dependency added — keeps the shared pnpm-lock untouched so CI's
  frozen-lockfile install and the deploy path are unaffected.
- GraphCanvas.tsx: SVG render driven by the sim — draggable + pinnable nodes
  (double-click to release), curved edges that fan parallel pairs, weight-sized
  geometric node shapes, fade-in on new nodes/edges, animated learned_from dash,
  risk-path lighting with the rest dimmed, label collision-avoidance.
- MetricsRail / LearningLoop / ActivityStream / SelectedNodePanel / encoding.ts:
  the mock's rails + stream + detail panel, light shadcn (ToggleGroup, ScrollArea,
  Badge, Button) on theme tokens; only the SVG is bespoke.
- GraphView polls /api/pods/:id/graph every 5s and diffs (positions preserved across
  refreshes), with a best-effort ws /api/events nudge. A stale selection (node gone
  across a poll) is dropped so the canvas can't dim entirely.

Backend (additive — materializer de-noise untouched):
- live.ts: buildLoop() (observe→store→predict→outcome→adapt counts, deepest-recent
  stage active) and buildActivity() (time-sorted typed feed, same isFilePath /
  ENGINEER_NOISE / signature de-noise) emitted alongside nodes/edges/metrics.
- demo.ts: fallback loop + activity so the panels render on the demo path.
- shared/src/graph.ts: additive optional PodGraph.loop / .activity + LearningStage /
  ActivityEvent types.

Verified: pnpm lint + -r typecheck + -r build pass; Playwright on the dev build
confirmed force layout (distinct positions, ticks on load under StrictMode), drag,
risk-mode dimming (opacity 0.14), selection panel, legend, and no overlaps on both
the clean demo and the 31-node live hairball.

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

frontend/src/components/graph/SelectedNodePanel.tsx

@@ -0,0 +1,51 @@
+import type { PodGraphNode } from '@podman/shared';
+import { Badge } from '@/components/ui/badge';
+import { statusColor, VIOLET } from './encoding.js';
+
+export function SelectedNodePanel({
+  node,
+  relCount,
+}: {
+  node: PodGraphNode | undefined;
+  relCount: number;
+}) {
+  if (!node) {
+    return (
+      <div className="flex h-full flex-col">
+        <p className="mb-2 text-xs font-medium uppercase tracking-wide text-muted-foreground">
+          Continual learning
+        </p>
+        <h3 className="mb-2 font-heading text-base font-medium">It learned</h3>
+        <p className="text-sm leading-relaxed text-muted-foreground">
+          The violet{' '}
+          <span className="font-medium" style={{ color: VIOLET }}>
+            learned_from
+          </span>{' '}
+          edges are ownership PodMan retained from accepted interventions — the graph gets sharper
+          every session. Click any node to trace its relationships, or drag to rearrange.
+        </p>
+      </div>
+    );
+  }
+  return (
+    <div className="flex h-full flex-col">
+      <p className="text-xs font-medium uppercase tracking-wide text-muted-foreground">
+        {node.kind}
+      </p>
+      <h3 className="mb-2 mt-0.5 font-heading text-lg font-medium">{node.label}</h3>
+      <div className="flex items-center justify-between border-b py-1.5 text-sm text-muted-foreground">
+        <span>Status</span>
+        <Badge variant="outline" style={{ color: statusColor(node.status) }}>
+          {node.status}
+        </Badge>
+      </div>
+      <div className="flex items-center justify-between border-b py-1.5 text-sm text-muted-foreground">
+        <span>Relationships</span>
+        <span className="font-medium text-foreground">{relCount}</span>
+      </div>
+      {node.summary && (
+        <p className="mt-2.5 text-sm leading-relaxed text-muted-foreground">{node.summary}</p>
+      )}
+    </div>
+  );
+}