feat: fuse engineer_states git truth into collision detector

Add getGitStates(podId) to db.ts — queries the engineer_states collection
written by scripts/podman-agent.mjs and returns a map keyed by engineer name.

In PodMan.onScreenFrame(), fuse before detectCollisions(): if an engineer has
changedFiles in engineer_states, force hasUnpushedChanges=true on their context.
This overrides Gemini vision's unreliable pixel-based guess with deterministic
local git state — preventing the money-moment collision from silently not firing.

Key assumption: LiveKit participant identity matches the --name arg used when
running the git watcher (e.g. identity "alice" → --name alice).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AaCFWMkYQmTcuPsxaaACft

backend/src/agent/podman.ts

@@ -5,6 +5,7 @@ import { analyzeFrame } from '../vision/gemini.js';
 import { detectCollisions } from '../collision/detector.js';
 import { getGithubState } from '../github/client.js';
 import { recordObservation, recordCollision, recordIntervention } from '../memory/store.js';
+import { getGitStates } from '../memory/db.js';
 import { recallSimilar } from '../memory/vectors.js';
 import { shouldIntervene, preferredAction } from '../memory/policy.js';
 import { speak } from '../voice/live.js';
@@ -36,6 +37,14 @@ export class PodMan {
     this.contexts.set(engineerId, ctx);
     await recordObservation(ctx);
 
+    // Fuse git ground truth: engineer_states written by scripts/podman-agent.mjs.
+    // Keyed by name (matches --name arg), same as LiveKit participant identity.
+    const gitStates = await getGitStates(this.podId);
+    for (const [id, c] of this.contexts) {
+      const git = gitStates.get(id);
+      if (git && git.changedFiles.length > 0) c.hasUnpushedChanges = true;
+    }
+
     const github = await getGithubState(); // cached
     const collisions = detectCollisions([...this.contexts.values()], github);
     for (const collision of collisions) await this.handle(collision);