test: add test infrastructure for frontend and server

- Frontend: vitest.config.ts with vue plugin + jsdom, dummy component test
- Server: in-memory SQLite test DB factory + Hono testClient helper + smoke test
- CI: add pnpm audit and server coverage threshold steps
- Root: vitest workspace config for multi-project test discovery

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

server/src/test-helpers/db.test.ts

@@ -0,0 +1,35 @@
+import { describe, it, expect } from 'vitest'
+import { eq } from 'drizzle-orm'
+import { createTestDb, insertTestBot } from './db.js'
+
+describe('test helpers', () => {
+  it('creates in-memory DB, inserts a bot, and queries it back', () => {
+    const { db, schema } = createTestDb()
+
+    const bot = insertTestBot(db, { name: 'SatoshiBot' })
+
+    const found = db
+      .select()
+      .from(schema.bots)
+      .where(eq(schema.bots.id, bot.id))
+      .get()
+
+    expect(found).toBeDefined()
+    expect(found!.name).toBe('SatoshiBot')
+    expect(found!.eloRating).toBe(1200)
+    expect(found!.webhookUrl).toBe('http://test.local/webhook')
+  })
+
+  it('each createTestDb is isolated', () => {
+    const { db: db1, schema: s1 } = createTestDb()
+    const { db: db2, schema: s2 } = createTestDb()
+
+    insertTestBot(db1, { name: 'BotInDb1' })
+
+    const inDb1 = db1.select().from(s1.bots).all()
+    const inDb2 = db2.select().from(s2.bots).all()
+
+    expect(inDb1).toHaveLength(1)
+    expect(inDb2).toHaveLength(0)
+  })
+})