chore: gitignore auto-generated mockServiceWorker.js

MSW postinstall auto-syncs public/mockServiceWorker.js via
package.json "msw.workerDirectory", so the update-msw.yml workflow
is redundant. Ignore the generated file and remove the workflow.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

Author: devmgn

.claude/rules/ci.md

@@ -7,7 +7,6 @@ paths:
 
 - `main` + feature branches, CI runs on non-main branches only
 - **lint.yml**: `pnpm check` — **test.yml**: `pnpm test:unit` — **build.yml**: `pnpm build` + upload `.next/`
-- **update-msw.yml**: Auto-update MSW worker (Renovate bot only)
 - Shared setup: ubuntu-24.04, 10min timeout, `pnpm/action-setup@v6`, Node.js from `mise.toml`, copies `.env.development` to `.env.local`
 - `upload-artifact` requires `include-hidden-files: true` for `.next/`
 - Action versions pinned by commit SHA

.github/workflows/update-msw.yml

@@ -236,3 +236,6 @@ scripts/actionlint
 
 # next-agents-md
 .next-docs/
+
+# MSW (auto-generated by postinstall via package.json "msw.workerDirectory")
+/public/mockServiceWorker.js