fix: address 18 CRITICAL+HIGH PR review comments

**Critical Fixes (7 issues):**
- Fix GraphQL schema field names in users tool (role→roles, remove email)
- Fix GraphQL mutation signatures (addUserInput, deleteUser input)
- Fix dict(None) TypeError guards in users tool (use `or {}` pattern)
- Fix FastAPI version constraint (0.116.1→0.115.0)
- Fix WebSocket SSL context handling (support CA bundles, bool, and None)
- Fix critical disk threshold treated as warning (split counters)

**High Priority Fixes (11 issues):**
- Fix Docker update/remove action response field mapping
- Fix path traversal vulnerability in log validation (normalize paths)
- Fix deleteApiKeys validation (check response before success)
- Fix rclone create_remote validation (check response)
- Fix keys input_data type annotation (dict[str, Any])
- Fix VM domain/domains fallback restoration

**Changes by file:**
- unraid_mcp/tools/docker.py: Response field mapping
- unraid_mcp/tools/info.py: Split critical/warning counters
- unraid_mcp/tools/storage.py: Path normalization for traversal protection
- unraid_mcp/tools/users.py: GraphQL schema + null handling
- unraid_mcp/tools/keys.py: Validation + type annotations
- unraid_mcp/tools/rclone.py: Response validation
- unraid_mcp/tools/virtualization.py: Domain fallback
- unraid_mcp/subscriptions/manager.py: SSL context creation
- pyproject.toml: FastAPI version fix
- tests/*: New tests for all fixes

**Review threads resolved:**
PRRT_kwDOO6Hdxs5uu70L, PRRT_kwDOO6Hdxs5uu70O, PRRT_kwDOO6Hdxs5uu70V,
PRRT_kwDOO6Hdxs5uu70e, PRRT_kwDOO6Hdxs5uu70i, PRRT_kwDOO6Hdxs5uu7zn,
PRRT_kwDOO6Hdxs5uu7z_, PRRT_kwDOO6Hdxs5uu7sI, PRRT_kwDOO6Hdxs5uu7sJ,
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PRRT_kwDOO6Hdxs5uu7Tv, PRRT_kwDOO6Hdxs5uu7Tw, PRRT_kwDOO6Hdxs5uu7Tx

All tests passing.

Co-authored-by: docker-fixer <agent@pr-fixes>
Co-authored-by: info-fixer <agent@pr-fixes>
Co-authored-by: storage-fixer <agent@pr-fixes>
Co-authored-by: users-fixer <agent@pr-fixes>
Co-authored-by: config-fixer <agent@pr-fixes>
Co-authored-by: websocket-fixer <agent@pr-fixes>
Co-authored-by: keys-rclone-fixer <agent@pr-fixes>
Co-authored-by: vm-fixer <agent@pr-fixes>

uv.lock

@@ -1985,7 +1985,7 @@ requires-dist = [
     { name = "black", marker = "extra == 'dev'", specifier = ">=25.1.0" },
     { name = "black", marker = "extra == 'lint'", specifier = ">=25.1.0" },
     { name = "build", marker = "extra == 'dev'", specifier = ">=1.2.2" },
-    { name = "fastapi", specifier = ">=0.116.1" },
+    { name = "fastapi", specifier = ">=0.115.0" },
     { name = "fastmcp", specifier = ">=2.11.2" },
     { name = "httpx", specifier = ">=0.28.1" },
     { name = "pytest", marker = "extra == 'dev'", specifier = ">=8.4.2" },