feat(db): extraction des embeddings + mode WAL + config DB provider-agnostic

- Ajout de la table de relation 1-1 NoteEmbedding pour alléger Model Note
- Refactor complet des actions IA sémantique et Memory Echo pour utiliser la jointure
- Migration propre des 85 embeddings locaux existants
- Ajout PRAGMA journal_mode=WAL pour la concurrence au sein de lib/prisma
- Ajout npm run db:switch pour configuration auto SQLite / PostgreSQL
- Fix du compilateur Turbopack et Next-PWA

keep-notes/scripts/switch-db.js

@@ -0,0 +1,48 @@
+// scripts/switch-db.js
+const fs = require('fs')
+const path = require('path')
+
+const envPath = path.join(__dirname, '..', '.env')
+const schemaPath = path.join(__dirname, '..', 'prisma', 'schema.prisma')
+
+const target = process.argv[2]
+if (!['sqlite', 'postgresql'].includes(target)) {
+  console.error("Usage: node scripts/switch-db.js [sqlite|postgresql]")
+  process.exit(1)
+}
+
+// 1. Update schema.prisma
+let schemaContent = fs.readFileSync(schemaPath, 'utf8')
+// Find the datasource db block and replace the provider
+schemaContent = schemaContent.replace(
+  /datasource db \{\s*provider\s*=\s*"[^"]+"/g,
+  `datasource db {\n  provider = "${target}"`
+)
+fs.writeFileSync(schemaPath, schemaContent)
+
+// 2. Update .env
+let envContent = fs.existsSync(envPath) ? fs.readFileSync(envPath, 'utf8') : ''
+const sqliteUrl = 'file:./dev.db'
+const pgUrl = 'postgresql://postgres:postgres@localhost:5432/keep_notes?schema=public'
+
+// Update or append DATABASE_URL
+if (target === 'sqlite') {
+  if (envContent.match(/^DATABASE_URL=.*$/m)) {
+    envContent = envContent.replace(/^DATABASE_URL=.*$/m, `DATABASE_URL="${sqliteUrl}"`)
+  } else {
+    envContent += `\nDATABASE_URL="${sqliteUrl}"`
+  }
+} else {
+  if (envContent.match(/^DATABASE_URL=.*$/m)) {
+    envContent = envContent.replace(/^DATABASE_URL=.*$/m, `DATABASE_URL="${pgUrl}"`)
+  } else {
+    envContent += `\nDATABASE_URL="${pgUrl}"`
+  }
+}
+
+fs.writeFileSync(envPath, envContent)
+
+console.log(`✅ Successfully switched database provider to ${target}`)
+console.log('You should now run:')
+console.log('  npx prisma generate')
+console.log('  npx prisma db push')