feat: add SvelteKit adapter

Add framework adapter for SvelteKit with:
- `getApp()` - get bknd app instance
- `serve()` - request handler for hooks.server.ts

Usage in hooks.server.ts:
```typescript
import { serve } from "bknd/adapter/sveltekit";
import config from "../bknd.config";

const bkndHandler = serve(config);

export const handle = async ({ event, resolve }) => {
  if (event.url.pathname.startsWith("/api/")) {
    return bkndHandler(event);
  }
  return resolve(event);
};
```

Includes:
- Adapter implementation (app/src/adapter/sveltekit/)
- Test suite
- Working example (examples/sveltekit/)
- Package exports and types

examples/sveltekit/bknd.config.ts

@@ -0,0 +1,52 @@
+import type { SvelteKitBkndConfig } from "bknd/adapter/sveltekit";
+import { em, entity, text, libsql } from "bknd";
+import { createClient } from "@libsql/client";
+
+const schema = em({
+  todos: entity("todos", {
+    title: text().required(),
+    done: text(),
+  }),
+});
+
+export default {
+  connection: libsql(
+    createClient({
+      url: "file:data.db",
+    })
+  ),
+  config: {
+    data: schema.toJSON(),
+    auth: {
+      enabled: true,
+      allow_register: true,
+      jwt: {
+        issuer: "bknd-sveltekit-example",
+        secret: "dev-secret-change-in-production-1234567890abcdef",
+      },
+      roles: {
+        admin: {
+          implicit_allow: true,
+        },
+        default: {
+          permissions: ["data.entity.read", "data.entity.create"],
+          is_default: true,
+        },
+      },
+    },
+  },
+  options: {
+    seed: async (ctx) => {
+      await ctx.app.module.auth.createUser({
+        email: "admin@example.com",
+        password: "password",
+        role: "admin",
+      });
+
+      await ctx.em.mutator("todos").insertMany([
+        { title: "Learn bknd", done: "true" },
+        { title: "Build with SvelteKit", done: "false" },
+      ]);
+    },
+  },
+} as const satisfies SvelteKitBkndConfig;