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/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
+);