feat(backend): scaffold PodMan agent pipeline + token server

Express server with /health and a LiveKit token endpoint. Module skeletons
for the full loop: vision (Gemini), GitHub fusion, collision detector (pure,
testable), intervention engine, and continual-learning memory store. Approve
native build scripts (esbuild/genai/protobufjs) at the workspace root.

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

backend/src/memory/store.ts

@@ -0,0 +1,27 @@
+import type { EngineerContext, Intervention } from '@podman/shared';
+
+/**
+ * Continual-learning memory: persist observations + intervention outcomes to
+ * MongoDB Atlas and embed file/feature notes into Voyage vectors so later
+ * sessions are sharper ("more useful the more you use it").
+ *
+ * TODO(memory): connect Atlas, store observations, record outcomes, embed via
+ * Voyage, and expose retrieval for the PodMan brain.
+ */
+export interface PodMemory {
+  recordObservation(ctx: EngineerContext): Promise<void>;
+  recordOutcome(intervention: Intervention, accepted: boolean): Promise<void>;
+}
+
+/** In-memory stub so the rest of the pipeline can run before Atlas is wired. */
+export function createInMemoryStore(): PodMemory {
+  const observations: EngineerContext[] = [];
+  return {
+    async recordObservation(ctx) {
+      observations.push(ctx);
+    },
+    async recordOutcome() {
+      /* no-op until Atlas is wired */
+    },
+  };
+}