test: badge E2E tests — fix __version wipe, extract idb_helpers, add render + workflow tests

Root cause fix: tests/_helpers/ae_defaults.ts was missing __version: 1, causing
store_versions.ts to wipe ae_loc from localStorage on every test page load. This
made trusted_access fall back to false, hiding the print button (can_print guard)
and failing all attendee workflow tests.

Changes:
- ae_defaults.ts: add __version: 1 with comment explaining the store_versions guard
- idb_helpers.ts: extract inject_badge_and_template() from print layout test into
  shared helper; now used by all three print/render test files
- event_badge_render.test.ts: new — 4 tests covering full_name_override priority,
  full_name fallback, duplex=0 hides badge back, duplex=1 shows badge back
- event_badge_attendee_workflow.test.ts: cleaned up (diagnostic code removed);
  all 3 tests now pass
- event_badge_print_layout.test.ts: renamed from badge_print_layout.test.ts;
  inline inject_idb() replaced with shared idb_helpers import
- event_badge_smoke.test.ts: renamed from event_badge.test.ts
- playwright.config.ts: use system /usr/bin/chromium on Arch Linux (avoids
  Playwright's bundled Chromium which requires Ubuntu libs not present on Arch)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/_helpers/ae_defaults.ts

@@ -1,4 +1,5 @@
 export const ae_app_local_data_defaults = {
+    __version: 1, // Must match AE_LOC_VERSION in src/lib/stores/store_versions.ts — store_versions.ts wipes ae_loc if version doesn't match
     last_page_reload: null,
     last_cache_refresh: Date.now(),
     cache_expired: false,

tests/_helpers/idb_helpers.ts

@@ -0,0 +1,56 @@
+/**
+ * IndexedDB injection helpers for Playwright tests.
+ *
+ * These functions execute inside the browser via page.evaluate() — they must be
+ * self-contained and cannot close over test-scope variables (only the single
+ * argument passed to page.evaluate is available).
+ *
+ * Standard pattern for using inject_badge_and_template:
+ *
+ *   await page.goto('/events/{event_id}/badges/{badge_id}/print');
+ *   await page.waitForLoadState('domcontentloaded');
+ *   await page.evaluate(inject_badge_and_template, { badge, template });
+ *   await page.reload();
+ *   await page.waitForLoadState('domcontentloaded');
+ *
+ * Why reload after injection: direct IDB writes bypass Dexie's internal
+ * change-notification system, so liveQuery subscribers don't re-fire.
+ * Reloading starts the page fresh against the already-populated IDB.
+ */
+
+/** Injects a badge and badge_template record into ae_events_db. */
+export async function inject_badge_and_template(
+    { badge, template }: { badge: object; template: object }
+): Promise<void> {
+    // Wait for Dexie to have fully initialised ae_events_db with its stores.
+    // domcontentloaded fires before Dexie's version migration runs, so the DB
+    // may not have the 'badge' / 'badge_template' stores yet when we arrive here.
+    await new Promise<void>((resolve, reject) => {
+        const poll = () => {
+            const req = indexedDB.open('ae_events_db');
+            req.onsuccess = () => {
+                const db = req.result as IDBDatabase;
+                const ready = db.objectStoreNames.contains('badge') &&
+                              db.objectStoreNames.contains('badge_template');
+                db.close();
+                if (ready) resolve();
+                else setTimeout(poll, 100);
+            };
+            req.onerror = () => reject((req as IDBRequest).error);
+        };
+        poll();
+    });
+
+    const db = await new Promise<IDBDatabase>((resolve, reject) => {
+        const req = indexedDB.open('ae_events_db');
+        req.onsuccess = () => resolve(req.result as IDBDatabase);
+        req.onerror   = () => reject((req as IDBRequest).error);
+    });
+    await new Promise<void>((resolve, reject) => {
+        const tx = db.transaction(['badge', 'badge_template'], 'readwrite');
+        tx.objectStore('badge').put(badge);
+        tx.objectStore('badge_template').put(template);
+        tx.oncomplete = () => { db.close(); resolve(); };
+        tx.onerror    = () => { db.close(); reject(tx.error); };
+    });
+}