feat: add agent_metrics table schema and Drizzle migration

Adds the agentMetrics table to SQLite schema for storing pre-computed
per-agent event counts (questions, subagents, compactions), enabling
listForRadar to fetch one row per agent instead of scanning log chunks.

Also fixes pre-existing Drizzle snapshot chain collision in meta/
(0035/0036 snapshots had wrong prevId due to parallel agent branches)
to unblock drizzle-kit generate.

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

apps/server/db/repositories/drizzle/agent-metrics.test.ts

@@ -0,0 +1,48 @@
+import { describe, it, expect } from 'vitest';
+import { createTestDatabase } from './test-helpers.js';
+import { agentMetrics } from '../../schema.js';
+
+describe('agentMetrics table', () => {
+  it('select from empty agentMetrics returns []', async () => {
+    const db = createTestDatabase();
+    const rows = await db.select().from(agentMetrics);
+    expect(rows).toEqual([]);
+  });
+
+  it('insert and select a metrics row round-trips correctly', async () => {
+    const db = createTestDatabase();
+    await db.insert(agentMetrics).values({
+      agentId: 'agent-abc',
+      questionsCount: 3,
+      subagentsCount: 1,
+      compactionsCount: 0,
+      updatedAt: new Date('2024-01-01T00:00:00Z'),
+    });
+    const rows = await db.select().from(agentMetrics);
+    expect(rows).toHaveLength(1);
+    expect(rows[0].agentId).toBe('agent-abc');
+    expect(rows[0].questionsCount).toBe(3);
+    expect(rows[0].subagentsCount).toBe(1);
+    expect(rows[0].compactionsCount).toBe(0);
+  });
+
+  it('agentId is primary key — duplicate insert throws', async () => {
+    const db = createTestDatabase();
+    await db.insert(agentMetrics).values({
+      agentId: 'agent-dup',
+      questionsCount: 0,
+      subagentsCount: 0,
+      compactionsCount: 0,
+      updatedAt: new Date(),
+    });
+    await expect(
+      db.insert(agentMetrics).values({
+        agentId: 'agent-dup',
+        questionsCount: 1,
+        subagentsCount: 0,
+        compactionsCount: 0,
+        updatedAt: new Date(),
+      })
+    ).rejects.toThrow();
+  });
+});

apps/server/db/schema.ts

@@ -513,6 +513,21 @@ export const agentLogChunks = sqliteTable('agent_log_chunks', {
 export type AgentLogChunk = InferSelectModel<typeof agentLogChunks>;
 export type NewAgentLogChunk = InferInsertModel<typeof agentLogChunks>;
 
+// ============================================================================
+// AGENT METRICS
+// ============================================================================
+
+export const agentMetrics = sqliteTable('agent_metrics', {
+  agentId: text('agent_id').primaryKey(),
+  questionsCount: integer('questions_count').notNull().default(0),
+  subagentsCount: integer('subagents_count').notNull().default(0),
+  compactionsCount: integer('compactions_count').notNull().default(0),
+  updatedAt: integer('updated_at', { mode: 'timestamp' }).notNull(),
+});
+
+export type AgentMetrics = InferSelectModel<typeof agentMetrics>;
+export type NewAgentMetrics = InferInsertModel<typeof agentMetrics>;
+
 // ============================================================================
 // CONVERSATIONS (inter-agent communication)
 // ============================================================================

apps/server/drizzle/0037_eager_devos.sql

@@ -0,0 +1,7 @@
+CREATE TABLE `agent_metrics` (
+	`agent_id` text PRIMARY KEY NOT NULL,
+	`questions_count` integer DEFAULT 0 NOT NULL,
+	`subagents_count` integer DEFAULT 0 NOT NULL,
+	`compactions_count` integer DEFAULT 0 NOT NULL,
+	`updated_at` integer NOT NULL
+);

apps/server/drizzle/meta/0035_snapshot.json

@@ -2,7 +2,7 @@
   "version": "6",
   "dialect": "sqlite",
   "id": "c84e499f-7df8-4091-b2a5-6b12847898bd",
-  "prevId": "5fbe1151-1dfb-4b0c-a7fa-2177369543fd",
+  "prevId": "443071fe-31d6-498a-9f4a-4a3ff24a46fc",
   "tables": {
     "accounts": {
       "name": "accounts",

apps/server/drizzle/meta/_journal.json

@@ -260,6 +260,13 @@
       "when": 1772798869413,
       "tag": "0036_icy_silvermane",
       "breakpoints": true
+    },
+    {
+      "idx": 37,
+      "version": "6",
+      "when": 1772828694292,
+      "tag": "0037_eager_devos",
+      "breakpoints": true
     }
   ]
-}
+}