migrate: replace NextAuth.js with Better Auth

- Install better-auth and @better-auth/drizzle-adapter
- Create src/lib/auth.ts with Better Auth configuration using bcrypt
- Update database schema: change auth table IDs from uuid to text
- Update route handler from /api/auth/[...nextauth] to /api/auth/[...all]
- Update tRPC context and middleware for Better Auth session handling
- Update client components to use Better Auth APIs (signIn, signOut)
- Update seed script with text-based IDs and correct account schema
- Fix type errors in wizard components (robotId, optional chaining)
- Fix API paths: api.robots.initialize -> api.robots.plugins.initialize
- Update auth router to use text IDs for Better Auth compatibility

Note: Auth tables were reset - users will need to re-register.

package.json

@@ -26,6 +26,7 @@
     "@auth/drizzle-adapter": "^1.11.1",
     "@aws-sdk/client-s3": "^3.989.0",
     "@aws-sdk/s3-request-presigner": "^3.989.0",
+    "@better-auth/drizzle-adapter": "^1.5.5",
     "@dnd-kit/core": "^6.3.1",
     "@dnd-kit/sortable": "^10.0.0",
     "@dnd-kit/utilities": "^3.2.2",
@@ -67,6 +68,7 @@
     "@types/js-cookie": "^3.0.6",
     "@types/ws": "^8.18.1",
     "bcryptjs": "^3.0.3",
+    "better-auth": "^1.5.5",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "cmdk": "^1.1.1",