test: fix stale imports after prompt-async-gate and model-core refactors

- prompt-async-gate.test.ts: refactor ced36bffc removed
  promptAsyncAfterSessionIdle in favor of the unified
  dispatchInternalPrompt({ mode: 'async', ... }). One call site at
  line 1441 was left behind. Replace it with the current API and pass
  the explicit dispatchTimeoutMs so the status-timeout semantics are
  preserved. Also switch the surrounding tests to the third-argument
  timeout form so Bun's typings stay happy.
- runtime-model-readers.test.ts: implementation moved to
  packages/model-core during the layering refactor; the orphaned test
  still pointed at './runtime-model-readers'. Switch to the package
  export via getModelCapabilities and keep the modality-reader
  coverage by deriving keys through the package API.

src/hooks/shared/prompt-async-gate.test.ts

@@ -7,7 +7,7 @@ import {
   releasePromptAsyncReservation,
 } from "./prompt-async-gate"
 
-function waitForPromise<T>(promise: Promise<T>, label: string): Promise<T> {
+async function waitForPromise<T>(promise: Promise<T>, label: string): Promise<T> {
   let timeoutID: ReturnType<typeof setTimeout> | undefined
   const timeout = new Promise<never>((_, reject) => {
     timeoutID = setTimeout(() => reject(new Error(`timed out waiting for ${label}`)), 1_000)
@@ -1424,7 +1424,7 @@ describe("dispatchInternalPrompt shared gate behavior", () => {
     })
   })
 
-  test("#given session.status hangs forever #when promptAsync gate checks activity #then it dispatches after status timeout", { timeout: 10_000 }, async () => {
+  test("#given session.status hangs forever #when promptAsync gate checks activity #then it dispatches after status timeout", async () => {
     // given
     let promptCalls = 0
     const neverSettles = new Promise<never>(() => {})
@@ -1438,17 +1438,19 @@ describe("dispatchInternalPrompt shared gate behavior", () => {
     }
 
     // when
-    const result = await promptAsyncAfterSessionIdle({
+    const result = await dispatchInternalPrompt({
+      mode: "async",
       client,
       sessionID: "ses_status_timeout",
       input: { path: { id: "ses_status_timeout" }, body: { parts: [] } },
       source: "test:status-timeout",
       settleMs: 0,
       postDispatchHoldMs: 0,
+      dispatchTimeoutMs: 50,
     })
 
     // then
     expect(result.status).toBe("dispatched")
     expect(promptCalls).toBe(1)
-  })
+  }, 10_000)
 })