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/model-suggestion-retry.test.ts

@@ -266,6 +266,31 @@ describe("promptWithModelSuggestionRetry", () => {
     expect(results[1]?.status).toBe("rejected")
   })
 
+  it("#given promptAsync retry just dispatched #when the same session is prompted again immediately #then the second caller is rejected by the gate", async () => {
+    // given
+    const promptMock = mock(async () => undefined)
+    const client = {
+      session: {
+        promptAsync: promptMock,
+      },
+    }
+    const args = {
+      path: { id: "session-post-dispatch-hold" },
+      body: {
+        parts: [{ type: "text", text: "hello" }],
+        model: { providerID: "anthropic", modelID: "claude-sonnet-4" },
+      },
+    }
+
+    // when
+    await promptWithModelSuggestionRetry(unsafeTestValue(client), args)
+    const second = promptWithModelSuggestionRetry(unsafeTestValue(client), args)
+
+    // then
+    await expect(second).rejects.toThrow("promptAsync skipped by gate: reserved")
+    expect(promptMock).toHaveBeenCalledTimes(1)
+  })
+
   it("should throw error from promptAsync directly on model-not-found error", async () => {
     // given a client that fails with model-not-found error
     const promptMock = mock().mockRejectedValueOnce({
@@ -436,6 +461,31 @@ describe("promptSyncWithModelSuggestionRetry", () => {
     expect(promptAsyncMock).toHaveBeenCalledTimes(0)
   })
 
+  it("#given sync prompt retry just dispatched #when the same session is prompted again immediately #then the second caller is rejected by the gate", async () => {
+    // given
+    const promptMock = mock(async () => undefined)
+    const client = {
+      session: {
+        prompt: promptMock,
+      },
+    }
+    const args = {
+      path: { id: "session-sync-post-dispatch-hold" },
+      body: {
+        parts: [{ type: "text", text: "hello" }],
+        model: { providerID: "anthropic", modelID: "claude-sonnet-4" },
+      },
+    }
+
+    // when
+    await promptSyncWithModelSuggestionRetry(unsafeTestValue(client), args)
+    const second = promptSyncWithModelSuggestionRetry(unsafeTestValue(client), args)
+
+    // then
+    await expect(second).rejects.toThrow("prompt skipped by gate: reserved")
+    expect(promptMock).toHaveBeenCalledTimes(1)
+  })
+
   it("should abort and throw timeout error when sync prompt hangs", async () => {
     // given a client where sync prompt never resolves unless aborted
     let receivedSignal: AbortSignal | undefined