feat(voyage): add playground sidebar with tabs + critique-card-list — v4.2 Step 10 [skip-docs]

Right-collapsible sidebar (320px) with 40px icon-rail when collapsed
(per critical decision #4 + research-06):

- 2-state FAB toggle (aria-expanded toggles aria-hidden on aside)
- Visible draft-count badge on FAB (mitigates 'forgot to export' friction)
- Two tabs:
    'Denne planen (N drafts)' — pending annotations
    'Alle revisjoner (M historiske)' — exported (Step 11 wires this)
- role="tablist" + role="tab" + aria-selected + tabindex roving
- ArrowLeft/ArrowRight keyboard nav between tabs
- .findings list of .critique-card per annotation
- Click on critique-card scrolls to anchor + .lint-annotation-glow
  1s pulse animation
- Sort-by-location (Hypothes.is pattern; line ASC)

Card visual: intent-badge (color-coded fix=green/change=blue/question=yellow/block=red),
ANN-NNNN ID, snippet preview, comment, exported-status.

Layout: main shifts margin-right: 320px above 1024px viewport so the
sidebar doesn't overlap the rendered artifact.

saveModalAsAnnotation + mountRender hooks now refresh the sidebar so
new drafts appear immediately and re-render preserves visibility.

Test coverage: tests/playground/voyage-playground.test.mjs +2 cases —
role="tablist", tabindex.

Verify: node --test tests/playground/voyage-playground.test.mjs ->
18 pass / 0 fail.
Full npm test: 592 pass / 0 fail / 2 skipped (Docker).

Refs plan.md Step 10 + critical decision #4 + research-06.

plugins/voyage/tests/playground/voyage-playground.test.mjs

@@ -112,3 +112,15 @@ test('voyage-playground.html declares 300ms grace constant (Step 9 adder-popup g
   const text = readFileSync(HTML, 'utf-8');
   assert.match(text, /300\s*ms|GRACE_MS\s*=\s*300|ADDER_GRACE_MS/i, '300ms grace period for adder-popup must be present');
 });
+
+// --- Step 10 — sidebar with tabs + critique-card-list ----------------
+
+test('voyage-playground.html includes role="tablist" (Step 10 sidebar tabs A11Y)', () => {
+  const text = readFileSync(HTML, 'utf-8');
+  assert.match(text, /role="tablist"/, 'sidebar must declare role="tablist" for A11Y');
+});
+
+test('voyage-playground.html declares tabindex (Step 10 focus management)', () => {
+  const text = readFileSync(HTML, 'utf-8');
+  assert.match(text, /tabindex/i, 'sidebar tabs must use tabindex for keyboard focus management');
+});