fix: address 18 PR review comments (threads 1-18)

Threads 1, 2, 3 — test hygiene:
- Move elicit_and_configure/elicit_reset_confirmation to module-level imports
  in unraid.py so tests can patch at unraid_mcp.tools.unraid.* (thread 2)
- Add return type annotations to _make_tool() in test_customization.py (thread 1)
- Replace unused _mock_ensure_started fixture params with @usefixtures (thread 3)

Thread 4 — remove dead 'connect' subaction from _SYSTEM_QUERIES; the subaction
was always rejected with a ToolError, creating an inconsistent contract.

Thread 5 — centralize two inline "query { online }" strings by reusing
_SYSTEM_QUERIES["online"]; add _DOCKER_QUERIES["_resolve"] for container-name
resolution instead of an inline query literal.

Threads 14, 15, 16, 17, 18 — test improvements:
- test-tools.sh: reword header to "broad non-destructive smoke coverage" (t14)
- test-tools.sh: add _json_payload() helper using jq --arg for safe JSON
  construction; replace all printf-based payloads (thread 15)
- test_input_validation.py: add return type annotations to _make_tool and all
  nested _run_test coroutines (thread 16)
- test_query_validation.py: extract _all_domain_dicts() shared helper to
  eliminate the duplicate 22-item registry (thread 17)
- test_query_validation.py: tighten regression threshold from 50 → 90 (thread 18)

pyproject.toml

@@ -71,7 +71,7 @@ classifiers = [
 # ============================================================================
 dependencies = [
     "python-dotenv>=1.1.1",
-    "fastmcp>=2.14.5",
+    "fastmcp>=3.0.0",
     "httpx>=0.28.1",
     "fastapi>=0.115.0",
     "uvicorn[standard]>=0.35.0",