chore(agent): track .agent/ planning tree in git

Remove the blanket .agent/ gitignore so the phase roadmap, user
stories, reports, and PLAN.md are versioned with the code. Only
runtime artifacts (.agent/phase-sessions/, .agent/pipeline.log)
remain ignored. Update AGENTS.md git protocol rule to match.

.agent/reports/02_story_import_documents.a2.validate

@@ -0,0 +1,21 @@
+ImportError while loading conftest '/var/home/ducoterra/Projects/Personal/brain_of_reese/tests/conftest.py'.
+tests/conftest.py:7: in <module>
+    from app.main import app as fastapi_app
+app/main.py:17: in <module>
+    from app.api.health import router as health_router
+app/api/health.py:7: in <module>
+    from app.db import db_available
+app/db.py:21: in <module>
+    engine = create_engine(get_settings().database_url, pool_pre_ping=True, future=True)
+             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+../../../.local/lib/python3.14/site-packages/sqlalchemy/util/deprecations.py:281: in warned
+    return fn(*args, **kwargs)  # type: ignore[no-any-return]
+           ^^^^^^^^^^^^^^^^^^^
+../../../.local/lib/python3.14/site-packages/sqlalchemy/engine/create.py:617: in create_engine
+    dbapi = dbapi_meth(**dbapi_args)
+            ^^^^^^^^^^^^^^^^^^^^^^^^
+../../../.local/lib/python3.14/site-packages/sqlalchemy/dialects/postgresql/psycopg.py:495: in import_dbapi
+    import psycopg
+E   ModuleNotFoundError: No module named 'psycopg'
+All checks passed!
+validation FAILED (see output above)