feat: implement delete note endpoint in server

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server.ts

@@ -1,5 +1,5 @@
 import { Application, Router } from "@oak/oak";
-import { getNotes, getNotesByDid } from "./src/data/db.ts";
+import { deleteNote, getNotes, getNotesByDid } from "./src/data/db.ts";
 
 const router = new Router();
 
@@ -20,6 +20,12 @@ router.get("/:did/notes", (ctx) => {
   ctx.response.body = getNotesByDid(did, cursor, limit);
 });
 
+router.delete("/:did/:rkey", (ctx) => {
+  const { did, rkey } = ctx.params;
+  deleteNote({ did, rkey });
+  ctx.response.status = 204;
+})
+
 const app = new Application();
 
 app.use(async (ctx, next) => {