fix(prompt-gate): pin duplicate prompt dispatches

Keep prompt reservations briefly after successful dispatch so rapid idle/message/error transitions cannot inject the same follow-up twice.

Route all production session prompt calls through the shared gate, restore skipped background resume state, release holds after abort/recovery paths, and preserve Ralph/ULW loop state when a dispatch is deferred.

Add regression coverage for session routing, static prompt route auditing, team-mode live messaging, model suggestion retries, call-omo-agent reuse, background parent wakes, runtime fallback, compaction recovery, Atlas, and Ralph/ULW loops.

src/shared/session-route.test.ts

@@ -0,0 +1,61 @@
+import { describe, expect, mock, test } from "bun:test"
+
+import { unsafeTestValue } from "../../test-support/unsafe-test-value"
+import { promptAsyncInDirectory } from "./session-route"
+
+describe("promptAsyncInDirectory", () => {
+  test("#given no session id is present #when routing a promptAsync request #then the helper rejects instead of using an ungated raw prompt", async () => {
+    // given
+    const promptAsync = mock(async () => ({ data: "sent" }))
+    const client = {
+      session: {
+        promptAsync,
+      },
+    }
+    const args = {
+      body: { parts: [{ type: "text", text: "continue" }] },
+    }
+
+    // when, then
+    await expect(
+      promptAsyncInDirectory(
+        unsafeTestValue(client),
+        unsafeTestValue(args),
+        "/workspace/project",
+      ),
+    ).rejects.toThrow("session id is required for routed promptAsync")
+    expect(promptAsync).toHaveBeenCalledTimes(0)
+  })
+
+  test("#given a routed prompt just dispatched #when the same session is prompted again immediately #then the route keeps the session reserved", async () => {
+    // given
+    const promptAsync = mock(async () => ({ data: "sent" }))
+    const client = {
+      session: {
+        promptAsync,
+      },
+    }
+    const args = {
+      path: { id: "ses_route_hold" },
+      body: { parts: [{ type: "text", text: "continue" }] },
+    }
+
+    // when
+    const first = await promptAsyncInDirectory(
+      unsafeTestValue(client),
+      unsafeTestValue(args),
+      "/workspace/project",
+    )
+    const second = promptAsyncInDirectory(
+      unsafeTestValue(client),
+      unsafeTestValue(args),
+      "/workspace/project",
+    )
+
+    // then
+    expect(first).toEqual({ data: "sent" })
+    await expect(second).rejects.toThrow("promptAsync skipped by gate: reserved")
+    expect(promptAsync).toHaveBeenCalledTimes(1)
+    expect(promptAsync.mock.calls[0]?.[0].query).toEqual({ directory: "/workspace/project" })
+  })
+})