refactor(tests): reorganize tests into unittest/ and e2e/ directories

- Move all unit tests from tests/ to tests/unittest/
- Add tests/e2e/ directory for end-to-end tests
- Update conftest.py for new test structure
- Add new tests for auth dependencies, policies, route injection
- Add new tests for run callbacks, create store, execution artifacts
- Remove obsolete tests for deleted persistence layer

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/tests/unittest/test_auth_errors.py

@@ -0,0 +1,76 @@
+"""Tests for auth error types and typed decode_token."""
+
+from datetime import UTC, datetime, timedelta
+
+import jwt as pyjwt
+
+from app.plugins.auth.domain.config import AuthConfig
+from app.plugins.auth.domain.errors import AuthErrorCode, AuthErrorResponse, TokenError
+from app.plugins.auth.domain.jwt import create_access_token, decode_token
+from app.plugins.auth.runtime.config_state import set_auth_config
+
+
+def test_auth_error_code_values():
+    assert AuthErrorCode.INVALID_CREDENTIALS == "invalid_credentials"
+    assert AuthErrorCode.TOKEN_EXPIRED == "token_expired"
+    assert AuthErrorCode.NOT_AUTHENTICATED == "not_authenticated"
+
+
+def test_token_error_values():
+    assert TokenError.EXPIRED == "expired"
+    assert TokenError.INVALID_SIGNATURE == "invalid_signature"
+    assert TokenError.MALFORMED == "malformed"
+
+
+def test_auth_error_response_serialization():
+    err = AuthErrorResponse(
+        code=AuthErrorCode.TOKEN_EXPIRED,
+        message="Token has expired",
+    )
+    d = err.model_dump()
+    assert d == {"code": "token_expired", "message": "Token has expired"}
+
+
+def test_auth_error_response_from_dict():
+    d = {"code": "invalid_credentials", "message": "Wrong password"}
+    err = AuthErrorResponse(**d)
+    assert err.code == AuthErrorCode.INVALID_CREDENTIALS
+
+
+# ── decode_token typed failure tests ──────────────────────────────
+
+_TEST_SECRET = "test-secret-for-jwt-decode-token-tests"
+
+
+def _setup_config():
+    set_auth_config(AuthConfig(jwt_secret=_TEST_SECRET))
+
+
+def test_decode_token_returns_token_error_on_expired():
+    _setup_config()
+    expired_payload = {"sub": "user-1", "exp": datetime.now(UTC) - timedelta(hours=1), "iat": datetime.now(UTC)}
+    token = pyjwt.encode(expired_payload, _TEST_SECRET, algorithm="HS256")
+    result = decode_token(token)
+    assert result == TokenError.EXPIRED
+
+
+def test_decode_token_returns_token_error_on_bad_signature():
+    _setup_config()
+    payload = {"sub": "user-1", "exp": datetime.now(UTC) + timedelta(hours=1), "iat": datetime.now(UTC)}
+    token = pyjwt.encode(payload, "wrong-secret-key-for-tests-minimum-32", algorithm="HS256")
+    result = decode_token(token)
+    assert result == TokenError.INVALID_SIGNATURE
+
+
+def test_decode_token_returns_token_error_on_malformed():
+    _setup_config()
+    result = decode_token("not-a-jwt")
+    assert result == TokenError.MALFORMED
+
+
+def test_decode_token_returns_payload_on_valid():
+    _setup_config()
+    token = create_access_token("user-123")
+    result = decode_token(token)
+    assert not isinstance(result, TokenError)
+    assert result.sub == "user-123"