fix(project): stabilize project deletion

- Guard renderer project list/get against stale initial loads
- Retry project zip/cache removal to handle transient Windows locks
- Surface deletion failures in UI and add regression tests

Made-with: Cursor

app/main/project/fsRetry.test.ts

@@ -0,0 +1,31 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+
+import { rmWithRetries } from './fsRetry';
+
+void test('rmWithRetries: retries on EPERM and then succeeds', async () => {
+  let calls = 0;
+  const rm = () => {
+    calls += 1;
+    if (calls < 3) {
+      const err = new Error('nope') as Error & { code: string };
+      err.code = 'EPERM';
+      throw err;
+    }
+    return Promise.resolve();
+  };
+  await rmWithRetries(rm, 'x', { force: true }, 5);
+  assert.equal(calls, 3);
+});
+
+void test('rmWithRetries: does not retry on ENOENT', async () => {
+  let calls = 0;
+  const rm = () => {
+    calls += 1;
+    const err = new Error('missing') as Error & { code: string };
+    err.code = 'ENOENT';
+    return Promise.reject(err);
+  };
+  await assert.rejects(() => rmWithRetries(rm, 'x', { force: true }, 5), /missing/);
+  assert.equal(calls, 1);
+});