feat: scaffold Brain of Reese — FastAPI RAG chat over Postgres 17 + pgvector

Foundation (phase 01, verified):
- FastAPI app: /api/health, /api/suggestions, /api/chat (placeholder),
  static frontend served locally (no CDN)
- Postgres 17 + pgvector via db/Containerfile + compose.yaml
  (podman compose up -d db), Alembic initial migration (documents,
  chunks with vector(768), query_log)
- LLM client targeting https://aipi.reeseapps.com/v1 (turbo/embed);
  scripts/llm_probe.py verified models + 768-dim embeddings live
- Conditional debugpy: imported only when DEBUGPY=1 (attach on demand,
  :5678); logging config for clean single-line logs
- Frontend shell: mobile-first chat + Sources pages, tokens, a11y baselines
- Tests: 24 unit+integration (99% coverage on app/), ruff + pyright clean,
  Playwright smoke E2E (3 tests) against a deterministic mock LLM
- Planning: .agent/PLAN.md (architecture + LOCKED decisions), AGENTS.md,
  6 user stories, 7 phase files (one story / one phase / one Playwright
  suite each)

compose.yaml

@@ -0,0 +1,49 @@
+# Brain of Reese — service orchestration.
+#
+#   Development:   podman compose up -d            # starts Postgres 17 + pgvector
+#   Full stack:    podman compose --profile prod up -d   # adds the app container
+#
+# The `db` image is built locally from `./db` (base: docker.io/postgres:17,
+# extended with the pgvector extension) so no non-official base image is used.
+
+name: brain-of-reese
+
+services:
+  db:
+    build:
+      context: ./db
+    image: brain-of-reese/db:pg17-vector
+    restart: unless-stopped
+    environment:
+      POSTGRES_USER: reese
+      POSTGRES_PASSWORD: reese
+      POSTGRES_DB: brain_of_reese
+    ports:
+      - "5432:5432"
+    volumes:
+      - pgdata:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U reese -d brain_of_reese"]
+      interval: 5s
+      timeout: 5s
+      retries: 12
+
+  app:
+    build:
+      context: .
+    image: brain-of-reese/app:latest
+    restart: unless-stopped
+    profiles: ["prod"]
+    depends_on:
+      db:
+        condition: service_healthy
+    environment:
+      BOR_ENVIRONMENT: production
+      BOR_DATABASE_URL: postgresql+psycopg://reese:reese@db:5432/brain_of_reese
+      BOR_LLM_BASE_URL: https://aipi.reeseapps.com/v1
+      # BOR_LLM_API_KEY: provide via shell env or your own env file — never commit it
+    ports:
+      - "8000:8000"
+
+volumes:
+  pgdata: