Merge pull request 'Install Yarn in the frontend CI job instead of relying on setup-node's cache' (#89) from fix/ci-frontend-yarn into main

setup-node's `cache: yarn` needs yarn already on PATH, and the Node it
installs does not ship one, so the frontend job failed at setup on every
run. Install the lockfile's Yarn 1.22.22 explicitly instead.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -34,11 +34,13 @@ jobs:
         working-directory: raggr-frontend
     steps:
       - uses: actions/checkout@v4.2.2
+      # No `cache: yarn` here: setup-node requires yarn to already be on PATH
+      # for that, and the Node it installs doesn't ship one.
       - uses: actions/setup-node@v4.4.0
         with:
           node-version: '22.14.0'
-          cache: yarn
-          cache-dependency-path: raggr-frontend/yarn.lock
+      - name: Install Yarn (lockfile v1)
+        run: npm install --global yarn@1.22.22
       - name: Install locked frontend dependencies
         run: yarn install --frozen-lockfile
       - name: Renderer tests