feat(e2e): add smart test caching and error toast catching

- results-db.ts: TestPassCache with consecutivePasses counter,
  recordTestResult(), shouldSkip(threshold=3), resetCache()
- wdio.conf.js: afterTest hook catches unexpected .toast.error/.load-error
  elements, records results to smart cache. FULL_RESCAN=1 bypasses caching

tests/e2e/infra/results-db.ts

@@ -33,9 +33,16 @@ export interface TestStepRow {
   created_at: string;
 }
 
+export interface TestPassCache {
+  testKey: string;
+  consecutivePasses: number;
+  lastPassedAt: string;
+}
+
 interface ResultsStore {
   runs: TestRunRow[];
   steps: TestStepRow[];
+  passCache: TestPassCache[];
 }
 
 export class ResultsDb {
@@ -51,12 +58,13 @@ export class ResultsDb {
   private load(): ResultsStore {
     if (existsSync(this.filePath)) {
       try {
-        return JSON.parse(readFileSync(this.filePath, 'utf-8'));
+        const data = JSON.parse(readFileSync(this.filePath, 'utf-8'));
+        return { runs: data.runs ?? [], steps: data.steps ?? [], passCache: data.passCache ?? [] };
       } catch {
-        return { runs: [], steps: [] };
+        return { runs: [], steps: [], passCache: [] };
       }
     }
-    return { runs: [], steps: [] };
+    return { runs: [], steps: [], passCache: [] };
   }
 
   private save(): void {
@@ -110,4 +118,61 @@ export class ResultsDb {
   getStepsForRun(runId: string): TestStepRow[] {
     return this.store.steps.filter(s => s.run_id === runId);
   }
+
+  // ── Pass Cache ──
+
+  private static makeTestKey(specFile: string, testTitle: string): string {
+    return `${specFile}::${testTitle}`;
+  }
+
+  recordTestResult(specFile: string, testTitle: string, passed: boolean): void {
+    const key = ResultsDb.makeTestKey(specFile, testTitle);
+    const entry = this.store.passCache.find(e => e.testKey === key);
+
+    if (passed) {
+      if (entry) {
+        entry.consecutivePasses += 1;
+        entry.lastPassedAt = new Date().toISOString();
+      } else {
+        this.store.passCache.push({
+          testKey: key,
+          consecutivePasses: 1,
+          lastPassedAt: new Date().toISOString(),
+        });
+      }
+    } else {
+      if (entry) {
+        entry.consecutivePasses = 0;
+      }
+    }
+    this.save();
+  }
+
+  shouldSkip(specFile: string, testTitle: string, threshold = 3): boolean {
+    const key = ResultsDb.makeTestKey(specFile, testTitle);
+    const entry = this.store.passCache.find(e => e.testKey === key);
+    return entry !== undefined && entry.consecutivePasses >= threshold;
+  }
+
+  resetCache(): void {
+    this.store.passCache = [];
+    this.save();
+  }
+
+  getCacheStats(threshold = 3): { total: number; skippable: number; threshold: number } {
+    const total = this.store.passCache.length;
+    const skippable = this.store.passCache.filter(e => e.consecutivePasses >= threshold).length;
+    return { total, skippable, threshold };
+  }
+}
+
+// ── Lazy singleton for use in wdio hooks ──
+
+let _singleton: ResultsDb | null = null;
+
+export function getResultsDb(): ResultsDb {
+  if (!_singleton) {
+    _singleton = new ResultsDb();
+  }
+  return _singleton;
 }