refactor: comprehensive code review fixes across 31 files

Addresses all critical, high, medium, and low issues from full codebase
review. 494 tests pass, ruff clean, ty type-check clean.

Security:
- Add tool_error_handler context manager (exceptions.py) — standardised
  error handling, eliminates 11 bare except-reraise patterns
- Remove unused exception subclasses (ConfigurationError, UnraidAPIError,
  SubscriptionError, ValidationError, IdempotentOperationError)
- Harden GraphQL subscription query validator with allow-list and
  forbidden-keyword regex (diagnostics.py)
- Add input validation for rclone create_remote config_data: injection,
  path-traversal, and key-count limits (rclone.py)
- Validate notifications importance enum before GraphQL request (notifications.py)
- Sanitise HTTP/network/JSON error messages — no raw exception strings
  leaked to clients (client.py)
- Strip path/creds from displayed API URL via _safe_display_url (health.py)
- Enable Ruff S (bandit) rule category in pyproject.toml
- Harden container mutations to strict-only matching — no fuzzy/substring
  for destructive operations (docker.py)

Performance:
- Token-bucket rate limiter (90 tokens, 9 req/s) with 429 retry backoff (client.py)
- Lazy asyncio.Lock init via _get_client_lock() — fixes event-loop
  module-load crash (client.py)
- Double-checked locking in get_http_client() for fast-path (client.py)
- Short hex container ID fast-path skips list fetch (docker.py)
- Cap resource_data log content to 1 MB / 5,000 lines (manager.py)
- Reset reconnect counter after 30 s stable connection (manager.py)
- Move tail_lines validation to module level; enforce 10,000 line cap
  (storage.py, docker.py)
- force_terminal=True removed from logging RichHandler (logging.py)

Architecture:
- Register diagnostic tools in server startup (server.py)
- Move ALL_ACTIONS computation to module level in all tools
- Consolidate format_kb / format_bytes into shared core/utils.py
- Add _safe_get() helper in core/utils.py for nested dict traversal
- Extract _analyze_subscription_status() from health.py diagnose handler
- Validate required config at startup — fail fast with CRITICAL log (server.py)

Code quality:
- Remove ~90 lines of dead Rich formatting helpers from logging.py
- Remove dead self.websocket attribute from SubscriptionManager
- Remove dead setup_uvicorn_logging() wrapper
- Move _VALID_IMPORTANCE to module level (N806 fix)
- Add slots=True to all three dataclasses (SubscriptionData, SystemHealth, APIResponse)
- Fix None rendering as literal "None" string in info.py summaries
- Change fuzzy-match log messages from INFO to DEBUG (docker.py)
- UTC-aware datetimes throughout (manager.py, diagnostics.py)

Infrastructure:
- Upgrade base image python:3.11-slim → python:3.12-slim (Dockerfile)
- Add non-root appuser (UID/GID 1000) with HEALTHCHECK (Dockerfile)
- Add read_only, cap_drop: ALL, tmpfs /tmp to docker-compose.yml
- Single-source version via importlib.metadata (pyproject.toml → __init__.py)
- Add open_timeout to all websockets.connect() calls

Tests:
- Update error message matchers to match sanitised messages (test_client.py)
- Fix patch targets for UNRAID_API_URL → utils module (test_subscriptions.py)
- Fix importance="info" → importance="normal" (test_notifications.py, http_layer)
- Fix naive datetime fixtures → UTC-aware (test_subscriptions.py)

Co-authored-by: Claude <claude@anthropic.com>

unraid_mcp/config/settings.py

@@ -5,6 +5,7 @@ and provides all configuration constants used throughout the application.
 """
 
 import os
+from importlib.metadata import PackageNotFoundError, version
 from pathlib import Path
 from typing import Any
 
@@ -30,8 +31,11 @@ for dotenv_path in dotenv_paths:
         load_dotenv(dotenv_path=dotenv_path)
         break
 
-# Application Version
-VERSION = "0.2.0"
+# Application Version (single source of truth: pyproject.toml)
+try:
+    VERSION = version("unraid-mcp")
+except PackageNotFoundError:
+    VERSION = "0.0.0"
 
 # Core API Configuration
 UNRAID_API_URL = os.getenv("UNRAID_API_URL")
@@ -39,7 +43,7 @@ UNRAID_API_KEY = os.getenv("UNRAID_API_KEY")
 
 # Server Configuration
 UNRAID_MCP_PORT = int(os.getenv("UNRAID_MCP_PORT", "6970"))
-UNRAID_MCP_HOST = os.getenv("UNRAID_MCP_HOST", "0.0.0.0")
+UNRAID_MCP_HOST = os.getenv("UNRAID_MCP_HOST", "0.0.0.0")  # noqa: S104 — intentional for Docker
 UNRAID_MCP_TRANSPORT = os.getenv("UNRAID_MCP_TRANSPORT", "streamable-http").lower()
 
 # SSL Configuration
@@ -54,7 +58,8 @@ else:  # Path to CA bundle
 # Logging Configuration
 LOG_LEVEL_STR = os.getenv("UNRAID_MCP_LOG_LEVEL", "INFO").upper()
 LOG_FILE_NAME = os.getenv("UNRAID_MCP_LOG_FILE", "unraid-mcp.log")
-LOGS_DIR = Path("/tmp")
+# Use /app/logs in Docker, project-relative logs/ directory otherwise
+LOGS_DIR = Path("/app/logs") if Path("/app").is_dir() else PROJECT_ROOT / "logs"
 LOG_FILE_PATH = LOGS_DIR / LOG_FILE_NAME
 
 # Ensure logs directory exists