fix(gate): knip sees the watch entry, the build must emit watch.html, and two hand copies are held

- The raw-source contract tests read files from disk (rawSources.testkit)
  instead of import.meta.glob, which knip counted as importing every src file —
  its unused-files lane could never name an orphan. knip now names
  src/watchMain.tsx as an entry (registered in docs/gates.md).
- vite build fails when index.html or watch.html is not emitted.
- The watch-entry import walk follows dynamic import() too.
- audit_metrics.py's plan-code patterns are held equal to the guard's.
- CrashBoundary is domain-free: it moves into components/ui.

frontend/src/components/ui/pressableSelectable.contract.test.ts

@@ -1,4 +1,5 @@
 import { describe, expect, it } from "vitest";
+import { readSources } from "../../lib/rawSources.testkit";
 
 // docs/DESIGN.md "Text stays selectable": a click surface whose text is a title or a name (a card, a
 // row, a person, a channel, a playlist, a log line) is `<Pressable selectable`, so its words select and
@@ -8,11 +9,11 @@ import { describe, expect, it } from "vitest";
 // pinned here with the reason: a new Pressable, or one that lost its flag, fails this test until
 // someone decides.
 
-const files = import.meta.glob(["../**/*.tsx", "!../**/*.test.*", "!../design-lab/**"], {
-  query: "?raw",
-  import: "default",
-  eager: true,
-}) as Record<string, string>;
+const files = readSources(__dirname, [
+  "../**/*.tsx",
+  "!../**/*.test.*",
+  "!../design-lab/**",
+]) as Record<string, string>;
 
 /** file → [how many plain Pressables, why they are not titles]. */
 const PLAIN: Record<string, [number, string]> = {