feat: make pageId routing always-on by default

Rename --experimental-page-id-routing to --page-id-routing and enable it
by default. Users can opt out with --no-page-id-routing if token overhead
is unacceptable or routing does not work as expected.

- Rename serverArgs.experimentalPageIdRouting to pageIdRouting and set
  default: true; describe text updated to reflect opt-out semantics.
- Update ToolHandler.ts schema injection and page resolution to use the
  new flag name.
- Drop the now-redundant delete of pageIdRouting from chrome-devtools-cli
  start options (was previously removing experimentalPageIdRouting).
- Update evaluate_script to use cliArgs.pageIdRouting and guard
  getPageById with a request.params.pageId check so passing the flag
  without a pageId no longer throws (mirrors the guard used in
  ToolHandler.ts).
- Improve pageIdSchema description: explain list_pages and selected-page
  fallback so the field is self-documenting.
- Fix generate-docs.ts to inject pageIdSchema for page-scoped tools so
  tool-reference.md surfaces pageId on every page-scoped tool; pass a
  slim flag so slim docs stay unchanged.
- Update eval scenarios to rely on the new default instead of passing
  --experimental-page-id-routing; update the example flag in the
  TestScenario JSDoc accordingly.
- Fix pageId type in script.test.ts (string -> number).
- Regenerated docs/tool-reference.md, README options section, and
  src/telemetry/{flag_usage_metrics,tool_call_metrics}.json.
- Add pageIdRouting/page-id-routing to the cli.test.ts default args
  fixture to reflect the new default.

Author: OrKoN

src/tools/script.ts

@@ -59,6 +59,7 @@ Example with arguments: \`(el) => {
         .describe(
           'Handle dialogs while execution. "accept", "dismiss", or string for response of window.prompt. Defaults to accept.',
         ),
+      ...(cliArgs?.pageIdRouting ? pageIdSchema : {}),
       ...(cliArgs?.categoryExtensions
         ? {
             serviceWorkerId: zod