refactor: shared load_dotenv in src/auth.py, used by all entry points

fix: use Gmail profile instead of userinfo endpoint for email lookup

feat: auto-save secrets to .env, auto-load on startup

feat: setup wizard loads existing config as defaults

feat: improved setup wizard with skippable steps and guided GCP flow

fix: add redirect URI instructions to setup wizard

feat: guided Google Cloud setup in wizard with browser links

fix: use run_http_async for proper async server startup

docs: add setup wizard instructions and AI agent setup guide

feat: add interactive setup wizard

docs: add design spec and implementation plan for Google integrations

test: add e2e tests for Google integrations

Merge branch 'main' into worktree-agent-ac45ea4c

feat: wire Google integrations into server and config

Merge branch 'worktree-agent-ac45ea4c'