fix: apply all PR review agent findings (silent failures, type safety, test gaps)

Addresses issues found by 4 parallel review agents (code-reviewer,
silent-failure-hunter, type-design-analyzer, pr-test-analyzer).

Source fixes:
- core/utils.py: add public safe_display_url() (moved from tools/health.py)
- core/client.py: rename _redact_sensitive → redact_sensitive (public API)
- core/types.py: add SubscriptionData.__post_init__ for tz-aware datetime
  enforcement; remove 6 unused type aliases (SystemHealth, APIResponse, etc.)
- subscriptions/manager.py: add exc_info=True to both except-Exception blocks;
  add except ValueError break-on-config-error before retry loop; import
  redact_sensitive by new public name
- subscriptions/resources.py: re-raise in autostart_subscriptions() so
  ensure_subscriptions_started() doesn't permanently set _subscriptions_started
- subscriptions/diagnostics.py: except ToolError: raise before broad except;
  use safe_display_url() instead of raw URL slice
- tools/health.py: move _safe_display_url to core/utils; add exc_info=True;
  raise ToolError (not return dict) on ImportError
- tools/info.py: use get_args(INFO_ACTIONS) instead of INFO_ACTIONS.__args__
- tools/{array,docker,keys,notifications,rclone,storage,virtualization}.py:
  add Literal-vs-ALL_ACTIONS sync check at import time

Test fixes:
- test_health.py: import safe_display_url from core.utils; update
  test_diagnose_import_error_internal to expect ToolError (not error dict)
- test_storage.py: add 3 safe_get tests for zero/False/empty-string values
- test_subscription_manager.py: add TestCapLogContentSingleMassiveLine (2 tests)
- test_client.py: rename _redact_sensitive → redact_sensitive; add tests for
  new sensitive keys and is_cacheable explicit-keyword form

unraid_mcp/subscriptions/diagnostics.py

@@ -19,6 +19,7 @@ from websockets.typing import Subprotocol
 from ..config.logging import logger
 from ..config.settings import UNRAID_API_KEY, UNRAID_API_URL
 from ..core.exceptions import ToolError
+from ..core.utils import safe_display_url
 from .manager import subscription_manager
 from .resources import ensure_subscriptions_started
 from .utils import build_ws_ssl_context, build_ws_url
@@ -162,6 +163,8 @@ def register_diagnostic_tools(mcp: FastMCP) -> None:
                         "note": "Connection successful, subscription may be waiting for events",
                     }
 
+        except ToolError:
+            raise
         except Exception as e:
             logger.error(f"[TEST_SUBSCRIPTION] Error: {e}", exc_info=True)
             return {"error": str(e), "query_tested": subscription_query}
@@ -193,7 +196,7 @@ def register_diagnostic_tools(mcp: FastMCP) -> None:
                 "environment": {
                     "auto_start_enabled": subscription_manager.auto_start_enabled,
                     "max_reconnect_attempts": subscription_manager.max_reconnect_attempts,
-                    "unraid_api_url": UNRAID_API_URL[:50] + "..." if UNRAID_API_URL else None,
+                    "unraid_api_url": safe_display_url(UNRAID_API_URL),
                     "api_key_configured": bool(UNRAID_API_KEY),
                     "websocket_url": None,
                 },