fix: address PR review threads (test-actions, diagnostics, docker, health, storage, plugin)

Resolves review threads:
- PRRT_kwDOO6Hdxs50R8VI (test-actions.sh: remove || echo "000" curl fallback)
- PRRT_kwDOO6Hdxs50R8VJ (test-actions.sh: JSON parse failures → FAIL not silent)
- PRRT_kwDOO6Hdxs50QdKd (diagnostics.py: sanitize raw exception text from ToolError)
- PRRT_kwDOO6Hdxs50QdKs (storage.py: unassigned uses unassignedDevices query)
- PRRT_kwDOO6Hdxs50Mwlk (docker.py: port_conflicts returns flat merged list)
- PRRT_kwDOO6Hdxs50Mwlo (docker.py: logs returns plain string not dict)
- PRRT_kwDOO6Hdxs50Mt5K (docker.py: unraid_docker logs format compatibility)
- PRRT_kwDOO6Hdxs50Mt5L (health.py: or {} null guards throughout)
- PRRT_kwDOO6Hdxs50Mt5r (docker.py: port_conflicts flat list backward compat)
- plugin.json: version synced to 0.4.4 to match pyproject.toml

Changes:
- test-actions.sh: curl exit code captured directly; JSON failures surface as FAIL
- diagnostics.py: 4 ToolError sites log exc_info=True, raise sanitized messages
- storage.py: unassigned action queries unassignedDevices instead of disks
- docker.py: logs action returns newline-joined string; port_conflicts merges
  containerPorts + lanPorts into a flat list for backward compatibility
- health.py: all nested dict lookups use `or {}` instead of `.get(k, {})` to
  handle explicit GraphQL null values

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

unraid_mcp/subscriptions/diagnostics.py

@@ -109,7 +109,10 @@ def register_diagnostic_tools(mcp: FastMCP) -> None:
             try:
                 ws_url = build_ws_url()
             except ValueError as e:
-                raise ToolError(str(e)) from e
+                logger.error("[TEST_SUBSCRIPTION] Invalid WebSocket URL configuration: %s", e)
+                raise ToolError(
+                    "Subscription test failed: invalid WebSocket URL configuration."
+                ) from e
 
             ssl_context = build_ws_ssl_context(ws_url)
 
@@ -137,7 +140,13 @@ def register_diagnostic_tools(mcp: FastMCP) -> None:
                 init_response = json.loads(response)
 
                 if init_response.get("type") != "connection_ack":
-                    raise ToolError(f"Connection failed: {init_response}")
+                    logger.error(
+                        "[TEST_SUBSCRIPTION] Connection not acknowledged: %s",
+                        init_response,
+                    )
+                    raise ToolError(
+                        "Subscription test failed: WebSocket connection was not acknowledged."
+                    )
 
                 # Send subscription
                 await websocket.send(
@@ -165,8 +174,10 @@ def register_diagnostic_tools(mcp: FastMCP) -> None:
         except ToolError:
             raise
         except Exception as e:
-            logger.error(f"[TEST_SUBSCRIPTION] Error: {e}", exc_info=True)
-            raise ToolError(f"Subscription test failed: {e!s}") from e
+            logger.error("[TEST_SUBSCRIPTION] Error: %s", e, exc_info=True)
+            raise ToolError(
+                "Subscription test failed: an unexpected error occurred. Check server logs for details."
+            ) from e
 
     @mcp.tool()
     async def diagnose_subscriptions() -> dict[str, Any]:
@@ -269,7 +280,9 @@ def register_diagnostic_tools(mcp: FastMCP) -> None:
             return diagnostic_info
 
         except Exception as e:
-            logger.error(f"[DIAGNOSTIC] Failed to generate diagnostics: {e}")
-            raise ToolError(f"Failed to generate diagnostics: {e!s}") from e
+            logger.error("[DIAGNOSTIC] Failed to generate diagnostics: %s", e, exc_info=True)
+            raise ToolError(
+                "Failed to generate diagnostics: an unexpected error occurred. Check server logs for details."
+            ) from e
 
     logger.info("Subscription diagnostic tools registered successfully")