Add attention inbox and AI usage observability

tests/ai-usage-repository.test.ts

@@ -0,0 +1,32 @@
+import { describe, expect, it } from 'vitest';
+import { AiUsageRepository } from '../src/database/ai-usage-repository.js';
+import { createTestDb } from './testUtils.js';
+
+describe('AiUsageRepository', () => {
+  it('aggregates cost, tokens, outcomes, and latency by actual model', () => {
+    const db = createTestDb();
+    const repo = new AiUsageRepository(db);
+    const now = Date.parse('2026-08-09T10:00:00Z');
+    repo.record({ operation: 'generateReply', requestedModel: 'router', actualModel: 'model-a', outcome: 'success', promptTokens: 100, completionTokens: 20, totalTokens: 120, costUsd: 0.0012, latencyMs: 400, createdAt: now });
+    repo.record({ operation: 'generateReply', requestedModel: 'model-a', actualModel: 'model-a', outcome: 'refusal', promptTokens: 40, completionTokens: 5, totalTokens: 45, costUsd: 0.0003, latencyMs: 200, createdAt: now });
+    repo.record({ operation: 'analyzeImage', requestedModel: 'model-b', outcome: 'error', latencyMs: 900, error: 'provider unavailable', createdAt: now });
+
+    expect(repo.getSummary(30, now)).toEqual({
+      days: 30,
+      requests: 3,
+      successes: 1,
+      refusals: 1,
+      errors: 1,
+      promptTokens: 140,
+      completionTokens: 25,
+      totalTokens: 165,
+      costUsd: 0.0015,
+      averageLatencyMs: 500,
+      models: [
+        { model: 'model-a', requests: 2, successes: 1, refusals: 1, errors: 0, promptTokens: 140, completionTokens: 25, totalTokens: 165, costUsd: 0.0015, averageLatencyMs: 300 },
+        { model: 'model-b', requests: 1, successes: 0, refusals: 0, errors: 1, promptTokens: 0, completionTokens: 0, totalTokens: 0, costUsd: 0, averageLatencyMs: 900 },
+      ],
+    });
+    db.close();
+  });
+});