refactor: remove obsolete sqlite3 native-binding self-heal

@cursor/sdk@1.0.19 (#28) drops the sqlite3 native addon in favor of Node's
built-in node:sqlite, so the self-heal that rebuilt sqlite3's binding under
Bun is no longer needed.

- Remove src/native-binding.ts and its tests
- Drop ensureSqliteBinding() from cursor-runtime loadCursorSdk and the
  sidecar agent backend (direct SDK import / client delegation)
- Remove the now-obsolete sqlite troubleshooting note from README

Verified: clean npm ci has no sqlite3, @cursor/sdk@1.0.19 imports cleanly,
and the opencode integration smoke test lists Cursor models.

Author: justin-carper

README.md

@@ -267,10 +267,6 @@ Override with `OPENCODE_CURSOR_SIDECAR=1` (always sidecar) or `OPENCODE_CURSOR_S
   on your `PATH`. Install Node.js 22+, or force the sidecar with `OPENCODE_CURSOR_SIDECAR=1`.
 - **"Running under Bun without a usable Node sidecar" warning.** Install Node.js 22+, or set
   `OPENCODE_CURSOR_SIDECAR=0` to accept in-process behavior and silence the warning.
-- **"Could not locate the bindings file" / `node_sqlite3.node` not found.** The `@cursor/sdk`
-  native sqlite3 addon was skipped during Bun install. The plugin self-heals on first load (needs
-  Node on `PATH`). If that fails, `cd` into the printed sqlite3 directory and run
-  `npx prebuild-install -r napi`.
 - **Plugin enabled but no `cursor` provider/models appear.** Stale opencode plugin cache. Pin an
   exact version (`@stablekernel/opencode-cursor@<version>`) or delete
   `~/.cache/opencode/packages/` and restart.

src/cursor-runtime.ts

@@ -6,27 +6,21 @@
  * dependency is missing) degrades gracefully into a clear error instead of
  * crashing opencode at startup.
  */
-import { ensureSqliteBinding } from "./native-binding.js";
-
 export type CursorSdkModule = typeof import("@cursor/sdk");
 
 let cached: Promise<CursorSdkModule> | undefined;
 
 export async function loadCursorSdk(): Promise<CursorSdkModule> {
   if (!cached) {
-    // @cursor/sdk eagerly requires sqlite3 (native addon); opencode's Bun
-    // install skips its build script, so repair the binding first if missing.
-    cached = ensureSqliteBinding()
-      .then(() => import("@cursor/sdk"))
-      .catch((err: unknown) => {
-        // Allow a later retry if the failure was transient.
-        cached = undefined;
-        const detail = err instanceof Error ? err.message : String(err);
-        throw new Error(
-          `[opencode-cursor] Failed to load "@cursor/sdk". Make sure it is installed ` +
-            `(\`npm install @cursor/sdk\`). Original error: ${detail}`,
-        );
-      });
+    cached = import("@cursor/sdk").catch((err: unknown) => {
+      // Allow a later retry if the failure was transient.
+      cached = undefined;
+      const detail = err instanceof Error ? err.message : String(err);
+      throw new Error(
+        `[opencode-cursor] Failed to load "@cursor/sdk". Make sure it is installed ` +
+          `(\`npm install @cursor/sdk\`). Original error: ${detail}`,
+      );
+    });
   }
   return cached;
 }

src/native-binding.ts

@@ -14,7 +14,6 @@ import { execSync } from "node:child_process";
 import { existsSync } from "node:fs";
 import { fileURLToPath } from "node:url";
 import { loadCursorSdk } from "../cursor-runtime.js";
-import { ensureSqliteBinding } from "../native-binding.js";
 import { SidecarClient, type AgentLike } from "./sidecar-client.js";
 
 export type { AgentLike, AgentRunLike, AgentSendOptions } from "./sidecar-client.js";
@@ -94,18 +93,10 @@ export function resolveSidecarScript(): string | undefined {
 
 function sidecarBackend(nodePath: string, scriptPath: string): AgentBackend {
   const client = new SidecarClient({ scriptPath, nodePath });
-  // The sidecar imports @cursor/sdk (which eagerly requires sqlite3's native
-  // binding) in the child process; repair the binding before first use.
   return {
     kind: "sidecar",
-    createAgent: async (options) => {
-      await ensureSqliteBinding();
-      return client.createAgent(options);
-    },
-    resumeAgent: async (agentId, options) => {
-      await ensureSqliteBinding();
-      return client.resumeAgent(agentId, options);
-    },
+    createAgent: (options) => client.createAgent(options),
+    resumeAgent: (agentId, options) => client.resumeAgent(agentId, options),
   };
 }