feat(FN-5419): add stash conflict modal gating and smart pull routing for m

Implements a pull-based merge workflow by wiring the merger pull helpers from the engine, extending the git pull and stash routes, and aligning the `MergeAdvanceNotice` and `StashConflictModal` components to gate dismissal on stash drop. The `run-audit` module is updated with pull mutation documenta

Fusion-Task-Id: FN-5419

Co-authored-by: Fusion (runfusion.ai) <noreply@runfusion.ai>
Fusion-Task-Id: FN-5419

packages/engine/src/__tests__/run-audit.test.ts

@@ -88,16 +88,51 @@ describe("run-audit provisioning mutation types", () => {
     ]);
   });
 
-  it("accepts smart-pull git mutation types", async () => {
+  it("accepts pull:fast-forward metadata shape", async () => {
     const store = new AuditStoreStub();
-    const auditor = createRunAuditor(store as unknown as TaskStore, { runId: "r1", agentId: "a1", taskId: "FN-5358" });
+    const auditor = createRunAuditor(store as unknown as TaskStore, { runId: "r1", agentId: "a1", taskId: "FN-5419" });
 
-    const types: GitMutationType[] = ["pull:fast-forward", "stash:pop-conflict", "push:origin"];
-    for (const type of types) {
-      await auditor.git({ type, target: "feature/worktree", metadata: { taskId: "FN-5358" } });
-    }
+    const type: GitMutationType = "pull:fast-forward";
+    await auditor.git({
+      type,
+      target: "/repo/.worktrees/integration",
+      metadata: {
+        taskId: "FN-5419",
+        worktreePath: "/repo/.worktrees/integration",
+        integrationBranch: "main",
+        remote: "origin",
+        fromSha: "1111111",
+        toSha: "2222222",
+        durationMs: 12,
+        succeeded: true,
+        behind: 0,
+        ahead: 0,
+      },
+    });
 
-    expect(store.events.map((event) => event.mutationType)).toEqual(types);
+    expect(store.events[0]?.mutationType).toBe(type);
+  });
+
+  it("accepts stash:pop-conflict metadata shape", async () => {
+    const store = new AuditStoreStub();
+    const auditor = createRunAuditor(store as unknown as TaskStore, { runId: "r1", agentId: "a1", taskId: "FN-5419" });
+
+    const type: GitMutationType = "stash:pop-conflict";
+    await auditor.git({
+      type,
+      target: "/repo/.worktrees/integration",
+      metadata: {
+        taskId: "FN-5419",
+        worktreePath: "/repo/.worktrees/integration",
+        stashSha: "abc123",
+        stashLabel: "fusion-autostash-FN-5419",
+        conflictedFiles: ["README.md"],
+        autostashOutcome: "conflict-needs-manual",
+        advice: "Resolve conflicts and drop stash when complete",
+      },
+    });
+
+    expect(store.events[0]?.mutationType).toBe(type);
   });
 
   it("records merge:scope:auto-widen git events", async () => {

packages/engine/src/index.ts

@@ -33,6 +33,12 @@ export {
   SquashAuditError,
   type MergerOptions,
   type AutostashOrphanRecord,
+  stashUnrelatedRootDirChanges,
+  dropAutostashHandle,
+  restoreUnrelatedRootDirChanges,
+  tryFastForwardFromOrigin,
+  getConflictedFiles,
+  type AutostashHandle,
 } from "./merger.js";
 export {
   resolveIntegrationBranch,
@@ -48,6 +54,9 @@ export {
   type HandoffResult,
   type MergeIntegrationRootResolution,
 } from "./merger-integration-worktree.js";
+export {
+  generateSyntheticRunId,
+} from "./run-audit.js";
 export {
   auditSquashMerge,
   formatSquashAuditReport,

packages/engine/src/merger.ts

@@ -1896,7 +1896,7 @@ function resetMergeWithWarn(rootDir: string, taskId: string, label: string): voi
  *  `rescueShas` lists any race-rescue stashes the autostash captured for
  *  late-dirty paths (concurrent dev edits during the merger run). They are
  *  surfaced separately so the caller can log them to the task feed. */
-interface AutostashHandle {
+export interface AutostashHandle {
   sha: string;
   label: string;
   rescueShas?: { sha: string; label: string }[];
@@ -2461,7 +2461,7 @@ export const __test__ = {
   notifyAutostashOrphans,
 };
 
-async function stashUnrelatedRootDirChanges(
+export async function stashUnrelatedRootDirChanges(
   rootDir: string,
   taskId: string,
 ): Promise<AutostashHandle | null> {
@@ -2688,7 +2688,7 @@ async function isAutostashLive(rootDir: string, sha: string): Promise<boolean> {
   }
 }
 
-async function dropAutostashHandle(
+export async function dropAutostashHandle(
   rootDir: string,
   taskId: string,
   handle: AutostashHandle,
@@ -3384,7 +3384,7 @@ async function restoreRescueAutostashes(
   return { unresolvedCount };
 }
 
-async function restoreUnrelatedRootDirChanges(
+export async function restoreUnrelatedRootDirChanges(
   rootDir: string,
   taskId: string,
   handle: AutostashHandle,
@@ -9926,7 +9926,7 @@ export async function aiMergeTask(
  *  NOTE: This is NOT FN-5350's integration-branch ref advance path. FN-5350
  *  advances refs/heads/<integration-branch> via compare-and-swap `git update-ref`.
  */
-async function tryFastForwardFromOrigin(
+export async function tryFastForwardFromOrigin(
   rootDir: string,
   taskId: string,
   integrationBranch: string,

packages/engine/src/run-audit.ts

@@ -288,11 +288,14 @@ export type GitMutationType =
    *   taskId?: string;
    *   worktreePath: string;
    *   integrationBranch: string;
+   *   remote?: string;
    *   fromSha: string;
    *   toSha: string;
    *   durationMs: number;
    *   succeeded: boolean;
    *   error?: string;
+   *   behind?: number;
+   *   ahead?: number;
    * }
    * ```
    */
@@ -324,7 +327,8 @@ export type GitMutationType =
    *   stashSha: string;
    *   stashLabel: string;
    *   conflictedFiles: string[];
-   *   advice: string;
+   *   autostashOutcome: "conflict-needs-manual" | "failed";
+   *   advice?: string;
    * }
    * ```
    */