feat: add better auth sqlite runtime and server-side session flow

package.json

@@ -6,7 +6,14 @@
     "dev": "next dev",
     "build": "next build",
     "start": "next start",
-    "lint": "eslint ."
+    "lint": "eslint .",
+    "typecheck": "tsc --noEmit",
+    "db:generate": "drizzle-kit generate",
+    "db:migrate": "node scripts/migrate.mjs",
+    "db:backup": "node scripts/backup.mjs",
+    "db:restore": "node scripts/restore.mjs",
+    "phase1:smoke": "node scripts/phase1-smoke.mjs",
+    "phase2:smoke": "node scripts/phase2-auth-smoke.mjs"
   },
   "dependencies": {
     "@ai-sdk/google": "^3.0.80",
@@ -33,11 +40,14 @@
     "@supabase/supabase-js": "^2.105.3",
     "@tailwindcss/postcss": "^4.3.0",
     "ai": "^6.0.197",
+    "better-auth": "^1.6.23",
+    "better-sqlite3": "^12.11.1",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "date-fns": "^4.4.0",
     "dexie": "^4.4.3",
     "dexie-react-hooks": "^4.4.0",
+    "drizzle-orm": "^0.45.2",
     "framer-motion": "^11.18.2",
     "lucide-react": "^1.17.0",
     "next": "^16.2.7",
@@ -55,11 +65,13 @@
     "zod": "^4.4.3"
   },
   "devDependencies": {
+    "@types/better-sqlite3": "^7.6.13",
     "@types/node": "^22.19.19",
     "@types/react": "^19.2.16",
     "@types/react-dom": "^19.2.3",
     "@types/uuid": "^10.0.0",
     "autoprefixer": "^10.5.0",
+    "drizzle-kit": "^0.31.10",
     "eslint": "^9.39.4",
     "eslint-config-next": "^16.2.7",
     "postcss": "^8.5.15",