feat(FN-3857): auto-recover merge deadlocks by recovering already merged ca

Adds auto-recovery for merge deadlocks when candidates have already been merged on main (FN-3857), including tests, documentation updates in AGENTS.md, and a patch changeset for the `@runfusion/fusion` package.

Fusion-Task-Id: FN-3857

packages/engine/src/__tests__/self-healing.test.ts

@@ -2600,7 +2600,7 @@ describe("SelfHealingManager", () => {
       managerWithRecovery.stop();
     });
 
-    it("filters out non-candidates", async () => {
+    it("filters out non-candidates but still evaluates paused failed candidates", async () => {
       const managerWithRecovery = new SelfHealingManager(store, {
         rootDir: "/tmp/test-project",
         getExecutingTaskIds: () => new Set(["FN-executing"]),
@@ -2613,12 +2613,17 @@ describe("SelfHealingManager", () => {
         { id: "FN-executing", column: "in-review", paused: false, status: "failed", mergeRetries: 3, mergeDetails: undefined, log: [] },
         { id: "FN-confirmed", column: "in-review", paused: false, status: "failed", mergeRetries: 3, mergeDetails: { mergeConfirmed: true }, log: [] },
       ]);
+      mockedExecSync.mockImplementation(() => "" as any);
 
       const result = await managerWithRecovery.recoverAlreadyMergedReviewTasks();
 
       expect(result).toBe(0);
       expect(store.updateTask).not.toHaveBeenCalled();
       expect(store.moveTask).not.toHaveBeenCalled();
+      expect(mockedExecSync).toHaveBeenCalledWith(
+        expect.stringContaining("Fusion-Task-Id: FN-paused"),
+        expect.any(Object),
+      );
 
       managerWithRecovery.stop();
     });

packages/engine/src/self-healing.ts

@@ -1807,7 +1807,6 @@ export class SelfHealingManager {
    *
    * Candidate filter:
    * - `column === "in-review"`
-   * - not paused
    * - `status === "failed"`
    * - `(mergeRetries ?? 0) >= MAX_AUTO_MERGE_RETRIES`
    * - `mergeDetails.mergeConfirmed !== true`
@@ -1830,7 +1829,6 @@ export class SelfHealingManager {
       const tasks = await this.store.listTasks({ column: "in-review", slim: true });
       const candidates = tasks.filter((task) =>
         task.column === "in-review" &&
-        !task.paused &&
         task.status === "failed" &&
         (task.mergeRetries ?? 0) >= MAX_AUTO_MERGE_RETRIES &&
         task.mergeDetails?.mergeConfirmed !== true &&