fix(kilo-sessions): handle sync throws in inflight cache

Wrap callback execution in a promise microtask so synchronous errors flow
through the existing `.catch()` and the in-flight entry is reliably cleaned
up. Update tests to await the microtask before asserting call count.

packages/opencode/src/kilo-sessions/inflight-cache.ts

@@ -37,7 +37,9 @@ export function withInFlightCache<T>(
         inflight: undefined,
       }
 
-  const task = cb()
+  // Guard against synchronous throws in `cb()` by forcing it into the promise chain.
+  // This ensures errors flow through the `.catch()` below and the cache entry is cleaned up.
+  const task = Promise.resolve().then(() => cb())
     .then((value) => {
       if (value === undefined) {
         // `undefined` is treated as a non-cacheable sentinel.

packages/opencode/test/kilo-sessions/inflight-cache.test.ts

@@ -39,6 +39,9 @@ describe("withInFlightCache", () => {
     const b = withInFlightCache(key, 10_000, cb)
 
     expect(a).toBe(b)
+    // cb() is invoked via a microtask in withInFlightCache().
+    // Allow it to run before asserting call count.
+    await Promise.resolve()
     expect(calls.count).toBe(1)
 
     job.resolve(123)