feat: comprehensive boilerplate improvements

Security & Stability:
- Add Next.js 16 proxy.ts for BetterAuth cookie-based auth protection
- Add rate limiting for API routes (src/lib/rate-limit.ts)
- Add Zod validation for chat API request bodies
- Add session auth check to chat and diagnostics endpoints
- Add security headers in next.config.ts (CSP, X-Frame-Options, etc.)
- Add file upload validation and sanitization in storage.ts

Core UX Components:
- Add error boundaries (error.tsx, not-found.tsx, chat/error.tsx)
- Add loading states (skeleton.tsx, spinner.tsx, loading.tsx files)
- Add toast notifications with Sonner
- Add form components (input.tsx, textarea.tsx, label.tsx)
- Add database indexes for performance (schema.ts)
- Enhance chat UX: timestamps, copy-to-clipboard, thinking indicator,
  error display, localStorage message persistence

Polish & Accessibility:
- Add Open Graph and Twitter card metadata
- Add JSON-LD structured data for SEO
- Add sitemap.ts, robots.ts, manifest.ts
- Add skip-to-content link and ARIA labels in site-header
- Enable profile page quick action buttons with dialogs
- Update Next.js 15 references to Next.js 16

Developer Experience:
- Add GitHub Actions CI workflow (lint, typecheck, build)
- Add Prettier configuration (.prettierrc, .prettierignore)
- Add .nvmrc pinning Node 20
- Add ESLint rules: import/order, react-hooks/exhaustive-deps
- Add stricter TypeScript settings (exactOptionalPropertyTypes,
  noImplicitOverride)
- Add interactive setup script (scripts/setup.ts)
- Add session utility functions (src/lib/session.ts)

All changes mirrored to create-agentic-app/template/

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/lib/schema.ts

@@ -1,52 +1,70 @@
-import { pgTable, text, timestamp, boolean } from "drizzle-orm/pg-core";
+import { pgTable, text, timestamp, boolean, index } from "drizzle-orm/pg-core";
 
-export const user = pgTable("user", {
-  id: text("id").primaryKey(),
-  name: text("name").notNull(),
-  email: text("email").notNull().unique(),
-  emailVerified: boolean("email_verified").default(false).notNull(),
-  image: text("image"),
-  createdAt: timestamp("created_at").defaultNow().notNull(),
-  updatedAt: timestamp("updated_at")
-    .defaultNow()
-    .$onUpdate(() => /* @__PURE__ */ new Date())
-    .notNull(),
-});
+export const user = pgTable(
+  "user",
+  {
+    id: text("id").primaryKey(),
+    name: text("name").notNull(),
+    email: text("email").notNull().unique(),
+    emailVerified: boolean("email_verified").default(false).notNull(),
+    image: text("image"),
+    createdAt: timestamp("created_at").defaultNow().notNull(),
+    updatedAt: timestamp("updated_at")
+      .defaultNow()
+      .$onUpdate(() => /* @__PURE__ */ new Date())
+      .notNull(),
+  },
+  (table) => [index("user_email_idx").on(table.email)]
+);
 
-export const session = pgTable("session", {
-  id: text("id").primaryKey(),
-  expiresAt: timestamp("expires_at").notNull(),
-  token: text("token").notNull().unique(),
-  createdAt: timestamp("created_at").defaultNow().notNull(),
-  updatedAt: timestamp("updated_at")
-    .$onUpdate(() => /* @__PURE__ */ new Date())
-    .notNull(),
-  ipAddress: text("ip_address"),
-  userAgent: text("user_agent"),
-  userId: text("user_id")
-    .notNull()
-    .references(() => user.id, { onDelete: "cascade" }),
-});
+export const session = pgTable(
+  "session",
+  {
+    id: text("id").primaryKey(),
+    expiresAt: timestamp("expires_at").notNull(),
+    token: text("token").notNull().unique(),
+    createdAt: timestamp("created_at").defaultNow().notNull(),
+    updatedAt: timestamp("updated_at")
+      .$onUpdate(() => /* @__PURE__ */ new Date())
+      .notNull(),
+    ipAddress: text("ip_address"),
+    userAgent: text("user_agent"),
+    userId: text("user_id")
+      .notNull()
+      .references(() => user.id, { onDelete: "cascade" }),
+  },
+  (table) => [
+    index("session_user_id_idx").on(table.userId),
+    index("session_token_idx").on(table.token),
+  ]
+);
 
-export const account = pgTable("account", {
-  id: text("id").primaryKey(),
-  accountId: text("account_id").notNull(),
-  providerId: text("provider_id").notNull(),
-  userId: text("user_id")
-    .notNull()
-    .references(() => user.id, { onDelete: "cascade" }),
-  accessToken: text("access_token"),
-  refreshToken: text("refresh_token"),
-  idToken: text("id_token"),
-  accessTokenExpiresAt: timestamp("access_token_expires_at"),
-  refreshTokenExpiresAt: timestamp("refresh_token_expires_at"),
-  scope: text("scope"),
-  password: text("password"),
-  createdAt: timestamp("created_at").defaultNow().notNull(),
-  updatedAt: timestamp("updated_at")
-    .$onUpdate(() => /* @__PURE__ */ new Date())
-    .notNull(),
-});
+export const account = pgTable(
+  "account",
+  {
+    id: text("id").primaryKey(),
+    accountId: text("account_id").notNull(),
+    providerId: text("provider_id").notNull(),
+    userId: text("user_id")
+      .notNull()
+      .references(() => user.id, { onDelete: "cascade" }),
+    accessToken: text("access_token"),
+    refreshToken: text("refresh_token"),
+    idToken: text("id_token"),
+    accessTokenExpiresAt: timestamp("access_token_expires_at"),
+    refreshTokenExpiresAt: timestamp("refresh_token_expires_at"),
+    scope: text("scope"),
+    password: text("password"),
+    createdAt: timestamp("created_at").defaultNow().notNull(),
+    updatedAt: timestamp("updated_at")
+      .$onUpdate(() => /* @__PURE__ */ new Date())
+      .notNull(),
+  },
+  (table) => [
+    index("account_user_id_idx").on(table.userId),
+    index("account_provider_account_idx").on(table.providerId, table.accountId),
+  ]
+);
 
 export const verification = pgTable("verification", {
   id: text("id").primaryKey(),