build(frontend)!: knip drops --production; plain knip stays

The production pass (7ed2ac4e, E32) asked "is this export used by what
ships?". No real hit: its only findings were 37 exports a test imports,
answered with 36 `@internal` JSDoc tags (E34 S2) — test-only exports, not
defects. Since then it has only ever asked for another tag. The tags go
with it (36, no longer read by anything), and so do the production-only
`!…!` exclusions in knip.jsonc and their register rows. Plain knip (unused
files, exports and dependencies) keeps running in the gate.

frontend/knip.jsonc

@@ -1,18 +1,6 @@
 {
   "$schema": "https://unpkg.com/knip@6/schema.json",
-  // `--production` (E32) asks a second question besides "is this used?": "is it used by the code
-  // that SHIPS?" — an export only a test reaches is either dead in the bundle or exported for its
-  // test, which then says so with a JSDoc `@internal` tag (knip skips those in production mode).
-  // What is not production code at all is excluded from the production project with a `!…!`
-  // pattern: the test kits, the e2e suite, and the two build-tooling modules the vite config
-  // imports (they shape the bundle but are not in it).
-  "project": [
-    "**/*.{ts,tsx,js}!",
-    "!**/*.testkit.ts!",
-    "!e2e/**!",
-    "!reactPlugin.ts!",
-    "!devOnlyGuard.ts!",
-  ],
+  "project": ["**/*.{ts,tsx,js}"],
   "playwright": {
     "config": ["playwright.config.ts"],
     "entry": ["e2e/**/*.@(spec|setup|measure).ts"],