Initial commit: ImpactFlow Discovery + Google OAuth auth layer

Discovery service (pre-existing): FastAPI + async SQLAlchemy + Alembic +
SQLite + Anthropic, with a five-prompt static UI that produces an Enneagram
+ Ikigai profile.

Auth implementation (this change set) follows
Impact_Flow_Auth_Plan_OAuth.html, adapted to the discovery_conversation /
discovery_profile schema:

- app/auth.py: Google OAuth registration, JWT issue/decode, dual-auth
  dependency (Bearer JWT or X-API-Key), refresh-token hashing, domain
  allow-list, synthetic api-key-admin user
- app/tracking.py: ActivityTrackingMiddleware + log_activity helper;
  tags machine-to-machine calls source=mcp
- app/routers/auth.py: /api/auth/{login,callback,refresh,logout},
  /api/me, /api/me/{stats,sessions,sessions/{id}}
- app/routers/activity.py: /api/activity, /api/activity/summary,
  /api/admin/activity, plus prune_old_activity (90-day retention)
- app/routers/discovery.py: every route now user-scoped via the auth
  dependency; /discovery/profile/{user_id} -> /discovery/profile/me
- alembic/versions/002_add_auth.py: users, refresh_tokens, activity_log
- tests/test_auth.py: 8 tests covering 401 paths, X-API-Key admin
  resolution, JWT round-trip, admin gating, domain allow-list
- README.md: Authentication section, expanded env-var table, updated
  data-model and API-reference tables
- .env.example: new GOOGLE_*, JWT_*, IMPACTFLOW_API_KEY, CORS_*,
  ALLOWED_EMAIL_DOMAINS placeholders
- .gitignore: also exclude data/*.log

Tests: 19/19 pass (11 pre-existing + 8 new). smoke_test.py exercises the
full discovery flow under X-API-Key plus 401 paths, OAuth login redirect,
activity logging, and /api/me/stats.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

alembic/env.py

@@ -0,0 +1,68 @@
+"""Alembic environment.
+
+Migrations run synchronously, so the async ``+aiosqlite`` driver in
+DATABASE_URL is stripped to a plain ``sqlite://`` URL here.
+"""
+import os
+from logging.config import fileConfig
+
+from alembic import context
+from dotenv import load_dotenv
+from sqlalchemy import engine_from_config, pool
+
+load_dotenv()
+
+config = context.config
+
+# Resolve the database URL from the environment, falling back to the ini value.
+_db_url = os.getenv("DATABASE_URL")
+if _db_url:
+    sync_url = _db_url.replace("+aiosqlite", "")
+    config.set_main_option("sqlalchemy.url", sync_url)
+else:
+    sync_url = config.get_main_option("sqlalchemy.url")
+
+# Make sure the directory for the SQLite file exists before connecting.
+if sync_url and ":///" in sync_url and "sqlite" in sync_url:
+    _path = sync_url.split(":///", 1)[1]
+    _dir = os.path.dirname(_path)
+    if _dir:
+        os.makedirs(_dir, exist_ok=True)
+
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+# Migrations are written by hand, so no autogenerate target metadata is needed.
+target_metadata = None
+
+
+def run_migrations_offline() -> None:
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online() -> None:
+    connectable = engine_from_config(
+        config.get_section(config.config_ini_section, {}),
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+    with connectable.connect() as connection:
+        context.configure(
+            connection=connection, target_metadata=target_metadata
+        )
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()