refactor: Co-locate server artifacts under apps/server/

Move drizzle/, dist/, and coverage/ into apps/server/ so all
server-specific artifacts live alongside the source they belong to.

- git mv drizzle/ → apps/server/drizzle/
- drizzle.config.ts: out → ./apps/server/drizzle
- tsconfig.json: outDir → ./apps/server/dist, exclude drizzle dir
- package.json: main/bin/clean point to apps/server/dist/
- vitest.config.ts: reportsDirectory → ./apps/server/coverage
- .gitignore: add coverage/ entry
- ensure-schema.ts: update getMigrationsPath() for new layout
- docs/database-migrations.md: update drizzle/ references

drizzle.config.ts

@@ -4,7 +4,7 @@ import { homedir } from 'node:os';
 
 export default defineConfig({
   schema: './apps/server/db/schema.ts',
-  out: './drizzle',
+  out: './apps/server/drizzle',
   dialect: 'sqlite',
   dbCredentials: {
     url: process.env.CW_DB_PATH ?? join(homedir(), '.cw', 'data', 'cw.db'),