review: harden version read + fix MonitoringScreen docstring

Address PR #1641 review feedback:

- Add readInspectorVersionSafe() (non-throwing) in core/node/version.ts and use
  it in the web backend, so a failure to resolve the root manifest hides the
  (cosmetic) version badge instead of crashing the backend at startup. Covered
  by tests for both the resolved and unresolvable paths.
- Update MonitoringScreen's docstrings: it now wraps every supplied screen in a
  ScreenStage (only the active tab mounts, cross-fading) rather than rendering
  just the active tab's node.

The third fetch-consolidation suggestion (one useInitialConfig instead of three
GET /api/config hooks) is tracked as a follow-up in #1643.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BrihGWcrM9JGRyu41nzZYw

clients/web/server/web-server-config.ts

@@ -14,13 +14,15 @@ import {
   LEGACY_AUTH_TOKEN_ENV,
 } from "../../../core/mcp/remote/constants.ts";
 import type { InitialConfigPayload } from "../../../core/mcp/remote/node/server.ts";
-import { readInspectorVersion } from "../../../core/node/version.ts";
+import { readInspectorVersionSafe } from "../../../core/node/version.ts";
 import { resolveSandboxPort } from "./sandbox-controller.js";
 
 // The single-source Inspector version (root package.json), read once at load.
 // The browser can't read the filesystem the way the CLI/TUI do, so the backend
-// reads it here and hands it to the client via GET /api/config.
-const inspectorVersion = readInspectorVersion(import.meta.url);
+// reads it here and hands it to the client via GET /api/config. Uses the
+// non-throwing read: the version is cosmetic, so a resolution failure hides the
+// badge (version omitted from the payload) rather than crashing the backend.
+const inspectorVersion = readInspectorVersionSafe(import.meta.url);
 
 export interface WebServerConfig {
   port: number;