feat(api): add experimental wellknown connections

packages/core/src/database/migration/20260716020354_kv.ts

@@ -0,0 +1,18 @@
+import { Effect } from "effect"
+import type { DatabaseMigration } from "../migration"
+
+export default {
+  id: "20260716020354_kv",
+  up(tx) {
+    return Effect.gen(function* () {
+      yield* tx.run(`
+        CREATE TABLE \`kv\` (
+          \`key\` text PRIMARY KEY,
+          \`value\` text NOT NULL,
+          \`time_created\` integer NOT NULL,
+          \`time_updated\` integer NOT NULL
+        );
+      `)
+    })
+  },
+} satisfies DatabaseMigration.Migration