chore(ci): drop unconsumed build artifact

- keep failure-only browser and database diagnostics
- stop retaining successful extension builds without a consumer

Author: xiaoland

.github/workflows/ci.yml

@@ -210,16 +210,6 @@ jobs:
       - name: Build the Firefox extension
         run: pnpm --filter @inkcre/client-webext build:firefox
 
-      - name: Retain the exact browser-extension artifacts
-        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
-        with:
-          name: client-webext-builds
-          path: |
-            apps/client-webext/.output/chrome-mv3
-            apps/client-webext/.output/firefox-mv2
-          if-no-files-found: error
-          retention-days: 7
-
       - name: Upload browser evidence on failure
         if: failure()
         uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1