findings R: coverage for the demo-ledger fixes (R-2, R-3, R-4, R-9) — tests only

- R-9: tests/kicad/project-sync.spec.ts gains an effect-asserting test —
  stages a self-contained footprint lib (ecc83 R_Axial as SyncFixture.pretty
  + absolute-uri fp-lib-table via a new stageAndOpen beforeOpen hook), presses
  Update PCB, and asserts the board's footprint references through
  kicadCollabSnapshot/kicadCollabTestItemBlob (R777, then R888 after a
  schematic rewrite + re-sync). Red-first: the dialog report said "Add R777"
  while the board stayed empty when the button click never landed.
- R-2: tests/kicad/via-snapshot-assert.spec.ts — two-via board, exact widths
  + no PCB_VIA::GetWidth wx assert line in the console.
- R-4: tests/web/console-copy.spec.ts — Ctrl/Cmd+C over a console selection
  fires `copy` (guard stops the keydown before wx); canvas pointerdown
  collapses the selection. ControlOrMeta: headless engines use the HOST copy
  accelerator regardless of the device UA.
- R-3: workers/cdn gets a vitest harness (package.json + lockfile) and
  test/index.test.ts with a workerd-like stub bucket (always-defined range):
  plain GET is 200/no Content-Range, Range → 206, HEAD/304/404/405/OPTIONS.
  Mutation-verified (pre-1ea35f7 gating → 2 reds). CI step added after the
  corpus lint; node_modules gitignored.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015j8uFzSjwRrAeJ85QWVLQa

.github/workflows/wasm-build.yml

@@ -401,6 +401,14 @@ jobs:
           npm run corpus:lint
           npm run tools:contract
 
+      # CDN worker unit tests (findings R-3: range-less GET must be 200, never 206).
+      - name: cdn worker unit tests
+        if: inputs.run_tests
+        working-directory: workers/cdn
+        run: |
+          npm ci
+          npm test
+
       # Browser binaries keyed on the lockfile (which pins the playwright version).
       # On a hit `playwright install` skips the downloads; --with-deps still
       # apt-installs its small OS dep set either way.