chore(ci): bound and cache the web-e2e Playwright install

.github/workflows/web-e2e.yml

@@ -169,8 +169,62 @@ jobs:
         env:
           VITE_E2E_HOOK: 'true'
 
+      # `--with-deps` bundles a browser download with an apt install, so a stall
+      # in either is unattributable. A step-level timeout alone would not help:
+      # it kills the step, not the stalled attempt, so nothing retries.
+      - name: Resolve the Playwright version
+        id: playwright
+        working-directory: tests/web-e2e
+        run: echo "version=$(node -p "require('@playwright/test/package.json').version")" >> "$GITHUB_OUTPUT"
+
+      - uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
+        id: playwright-cache
+        with:
+          path: ~/.cache/ms-playwright
+          key: playwright-${{ runner.os }}-${{ steps.playwright.outputs.version }}
+
       - name: Install Playwright Chromium
-        run: pnpm --filter @cipherbox/web-e2e exec playwright install --with-deps chromium
+        if: steps.playwright-cache.outputs.cache-hit != 'true'
+        timeout-minutes: 10
+        run: |
+          # The marker records the install's own status, so a stall is told
+          # apart from the command exiting 124 on its own. `--kill-after`
+          # matters most: without it `timeout` waits forever on a child that
+          # ignores SIGTERM, which is the stall this step exists to bound.
+          marker="$RUNNER_TEMP/playwright-browser-status"
+          for attempt in 1 2 3; do
+            rm -f "$marker"
+            # shellcheck disable=SC2016  # the inner shell expands $? and $1, not this one
+            timeout --kill-after=30 150 bash -c \
+              'pnpm --filter @cipherbox/web-e2e exec playwright install chromium; echo "$?" > "$1"' _ "$marker" || true
+            if [ -f "$marker" ]; then
+              install_status=$(cat "$marker")
+              if [ "$install_status" -eq 0 ]; then
+                exit 0
+              fi
+              echo "::error::playwright install chromium failed with status $install_status"
+              exit "$install_status"
+            fi
+            echo "::warning::playwright install chromium stalled past 150s (attempt $attempt of 3)"
+          done
+          echo "::error::playwright install chromium stalled on every attempt"
+          exit 1
+
+      # The runner image already carries Chromium's shared libraries, so this
+      # is a no-op on a healthy runner — a passing run installs nothing and
+      # takes seconds. It stays only to cover an image that drops one.
+      #
+      # So a stall here must not gate the suite: apt is bounded, never retried
+      # (Playwright runs it under sudo, and a killed attempt leaves a root-owned
+      # apt-get holding the dpkg lock that the next attempt dies on), and a
+      # failure warns rather than fails. If a library really is missing, the
+      # smoke slice says so in the browser launch error.
+      - name: Install the Playwright system dependencies
+        timeout-minutes: 6
+        run: |
+          timeout --kill-after=30 240 \
+            pnpm --filter @cipherbox/web-e2e exec playwright install-deps chromium \
+            || echo "::warning::playwright install-deps did not complete; the smoke slice shows whether a library is actually missing"
 
       # Named `test:e2e`, not `test`: the workspace-wide `Test` gate runs no
       # suite that needs a live stack.