fix: force interactive login shell for bash containers

Detached containers with tty: true still exited immediately because a
plain /bin/bash invocation exits with code 0 when stdin is not connected.

- Detect when the container CMD is /bin/bash or bash and exec an
  interactive login shell () after dropping privileges
- Keep the generic  path for non-shell commands
- Bump compiler_version to v4 to force a fresh image build

Quality gates:
- pytest tests/unit: 219 passed
- ruff: clean on changed files
- mypy: clean on changed files

apps/api/tests/.pi-map.index.md

@@ -2,7 +2,7 @@
 dir: apps/api/tests
 
 ## role
-Provides shared test infrastructure and fixtures for API integration testing
+Provides shared test infrastructure and fixtures for the API application's test suite.
 ## parent
 index: apps/api/.pi-map.index.md
 map: apps/api/.pi-map.md

apps/api/tests/.pi-map.md

@@ -4,11 +4,11 @@ dir: apps/api/tests
 index: apps/api/tests/.pi-map.index.md
 
 ## role
-Provides shared test infrastructure and fixtures for API integration testing
+Provides shared test infrastructure and fixtures for the API application's test suite.
 ## files
 - conftest.py | Provides shared pytest fixtures for testing a FastAPI application with async SQLite database, authenticated clients, and test data setup. | exp: func:test_client() → Generator[TestClient, None, None], call:create_async_engine, call:engine.begin, call:conn.run_sync, call:asyncio.run, call:init_db, call:async_sessionmaker, call:patch, call:TestClient, call:app.dependency_overrides.pop, call:engine.dispose, func:init_db(), call:engine.begin, call:conn.run_sync, func:override_get_db_session() → AsyncGenerator[AsyncSession, None], call:async_sessionmaker, func:db_session(test_client) → AsyncGenerator[AsyncSession, None], call:app.dependency_overrides.get, call:override_fn, call:gen.asend, call:gen.aclose, call:create_async_engine, call:engine.begin, call:conn.run_sync, call:async_sessionmaker, call:engine.dispose, func:authenticated_client(test_client) → Generator[TestClient, None, None], call:str, call:uuid.uuid4, call:Settings, call:app.dependency_overrides.get, call:override_fn, call:gen.asend, call:User, call:uuid.UUID, call:session.add, call:session.commit, call:gen.aclose, call:asyncio.run, call:create_test_user, call:create_session_cookie, call:test_client.cookies.set, func:create_test_user(), call:app.dependency_overrides.get, call:override_fn, call:gen.asend, call:User, call:uuid.UUID, call:session.add, call:session.commit, call:gen.aclose, func:test_project_and_repo(authenticated_client) → tuple[str, str], call:uuid.uuid4, call:Settings, call:authenticated_client.cookies.get, call:decode_session_cookie, call:uuid.UUID, call:asyncio.run, call:get_user_id, call:app.dependency_overrides.get, call:override_fn, call:gen.asend, call:Project, call:session.add, call:GitRepository, call:session.commit, call:gen.aclose, call:create_project_and_repo, call:str, raise:RuntimeError, func:get_user_id(), call:Settings, call:authenticated_client.cookies.get, call:decode_session_cookie, call:uuid.UUID, func:create_project_and_repo(), call:app.dependency_overrides.get, call:override_fn, call:gen.asend, call:Project, call:session.add, call:GitRepository, call:session.commit, call:gen.aclose, func:admin_client(test_client) → Generator[TestClient, None, None], call:str, call:uuid.uuid4, call:Settings, call:app.dependency_overrides.get, call:override_fn, call:gen.asend, call:User, call:uuid.UUID, call:session.add, call:session.commit, call:gen.aclose, call:asyncio.run, call:create_admin_user, call:create_session_cookie, call:test_client.cookies.set, func:create_admin_user(), call:app.dependency_overrides.get, call:override_fn, call:gen.asend, call:User, call:uuid.UUID, call:session.add, call:session.commit, call:gen.aclose | dep: asyncio, os, typing, unittest.mock, pytest, pytest_asyncio, fastapi.testclient, sqlalchemy.ext.asyncio, src.config, src.models.base, src.main, src.auth.dependencies, uuid, src.auth.session, src.models.user.user, src.models.project.project, src.models.project.git_repository, fastapi, sqlalchemy, aiosqlite, src.models, src.auth
 ## arch
-Pytest fixture-based architecture with async SQLite test database, dependency injection overrides, and authenticated client factories for FastAPI endpoint testing
+Pytest fixture-based testing architecture with async SQLite test database, dependency injection overrides, and authenticated client factories using FastAPI's TestClient.
 ## tags
 call:app.dependency, call:create, overrides.get, call:override, fn, call:gen.asend, call:gen.aclose, user
 ## symbols

apps/api/tests/unit/.pi-map.index.md

@@ -2,7 +2,7 @@
 dir: apps/api/tests/unit
 
 ## role
-Contains comprehensive unit tests for the API application's core services, utilities, and infrastructure components.
+Contains unit tests for the API application's core services, utilities, and infrastructure components.
 ## parent
 index: apps/api/tests/.pi-map.index.md
 map: apps/api/tests/.pi-map.md

apps/api/tests/unit/.pi-map.md

@@ -4,7 +4,7 @@ dir: apps/api/tests/unit
 index: apps/api/tests/unit/.pi-map.index.md
 
 ## role
-Contains comprehensive unit tests for the API application's core services, utilities, and infrastructure components.
+Contains unit tests for the API application's core services, utilities, and infrastructure components.
 ## files
 - __init__.py | Empty file with no functionality
 - test_alembic_migrations.py | Unit tests that verify Alembic database migrations are importable, have correct revision identifiers, and declare expected dependencies without requiring a live database. | exp: func:test_home_directory_migration_imports_and_rewrites() → None, call:Path, call:migration_path.exists, call:importlib.util.spec_from_file_location, call:importlib.util.module_from_spec, call:spec.loader.exec_module, call:callable, func:test_merge_migration_resolves_heads() → None, call:Path, call:migration_path.exists, call:importlib.util.spec_from_file_location, call:importlib.util.module_from_spec, call:spec.loader.exec_module, call:callable, func:test_remove_pi_agent_repo_mount_migration_imports() → None, call:Path, call:migration_path.exists, call:importlib.util.spec_from_file_location, call:importlib.util.module_from_spec, call:spec.loader.exec_module, call:callable | dep: importlib.util, pathlib, pytest, importlib
@@ -30,7 +30,7 @@ Contains comprehensive unit tests for the API application's core services, utili
 - test_readiness_probe.py | Unit tests for a Docker container readiness probe service that executes commands via docker exec with retry logic. | exp: class:TestExecuteProbe, class:TestIntegrationScenarios | dep: unittest.mock, src.services.shared.readiness_probe, subprocess
 - test_ssh_keys.py | Unit tests for SSH key preparation functionality including file creation, permissions, ownership, and error handling | exp: class:TestPrepareSshKeyFiles | dep: os, pathlib, unittest.mock, pytest, src.services.shared.ssh_keys
 ## arch
-Standard Python unittest/pytest pattern with heavy use of mocking (subprocess, filesystem, database) to isolate components; tests are organized by service/domain with each file targeting a single module/class; no internal dependencies between test files.
+Comprehensive unit test suite using mocked dependencies to test business logic in isolation, covering database migrations, configuration, Docker operations, Git workflows, file services, event handling, health monitoring, and SSH/security utilities.
 ## tags
 test, url, call:notification, git, call:, home, merge, call:db
 ## symbols

apps/api/tests/unit/test_manifest_compiler.py

@@ -270,6 +270,7 @@ def test_compile_dockerfile_starts_as_root_and_drops_privileges() -> None:
     entrypoint = compile_entrypoint(manifest)
 
     assert "USER dev" not in dockerfile
+    assert 'exec runuser -u dev -- /bin/bash -il' in entrypoint
     assert 'exec runuser -u dev -- "$@"' in entrypoint