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.

CLAUDE.md

@@ -13,7 +13,7 @@ router-free navigation provider.
 ## The gate — never merge or ship red
 
 The local gate is **ruff (`check` + `format --check`) + basedpyright (backend) + the lock check + typecheck (3 tsc projects) +
-eslint + prettier --check + knip (both modes) + vitest + vite build + pytest + pip-audit + npm audit**, then a coverage report (no threshold). It runs
+eslint + prettier --check + knip + vitest + vite build + pytest + pip-audit + npm audit**, then a coverage report (no threshold). It runs
 before every `release` merges and on every `publish`, which **refuses to build on failure — there is deliberately no `--skip`
 flag**; a release also requires the Playwright suite, and the image must pass a Trivy scan before it is pushed. Run it and get it
 green **before** any merge, release, or handing work to review.