G0.4: add psycopg2-binary so migrations run inside the image

Alembic runs synchronously, so the container needs a sync driver. Without it
migrations fail on a fresh deploy while passing on any developer machine that
happens to have psycopg2 — exactly the class of gap that only appears in
production.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

pyproject.toml

@@ -17,6 +17,11 @@ dependencies = [
     "pydantic-settings>=2.6",
     "sqlalchemy[asyncio]>=2.0",
     "asyncpg>=0.30",
+    # Alembic runs synchronously (env.py strips +asyncpg), so the image needs a
+    # sync driver too. Without it migrations fail INSIDE the container while
+    # passing on a developer machine that happens to have it — the kind of gap
+    # that only shows up on a fresh deploy.
+    "psycopg2-binary>=2.9",
     "alembic>=1.14",
     "httpx>=0.27",
     "boto3>=1.35",