feat(FN-2924): merge fusion/fn-2924

- Add task provenance display to TaskDetailModal, surfacing AI-generated merge commit summaries so users understand when and why tasks landed
- New `ai-summarize` module in core with structured commit summarization logic and tests
- Extend CLI `fn task show` with provenance output
- Refactor merger to produce cleaner merge commit messages with task context
- Update SettingsModal to expose AI summarization toggle (hidden behind feature flag)
- Adjust QuickChatFAB styling for theme compatibility
- Update scheduler and node-routing policy tests to match new behavior
- Add changeset for `@runfusion/fusion` minor release

Commits merged:
- feat(FN-2924): display task provenance in dashboard and cli
- feat(FN-2971): merge fusion/fn-2971
- feat(FN-2947): merge fusion/fn-2947
- feat(FN-2970): merge fusion/fn-2970
- feat(FN-2956): merge fusion/fn-2956

Files changed:
.changeset/add-ai-merge-commit-summary.md          |   5 +
 docs/cli-reference.md                              |   3 +-
 docs/settings-reference.md                         |   3 +
 packages/cli/src/commands/__tests__/task.test.ts   |  44 ++++-
 packages/cli/src/commands/task.ts                  |  55 +++++++
 packages/core/src/__tests__/ai-summarize.test.ts   |  64 ++++++++
 packages/core/src/ai-summarize.ts                  | 114 +++++++++++++
 packages/core/src/index.ts                         |   3 +
 packages/core/src/settings-schema.ts               |   1 +
 packages/core/src/types.ts                         |   4 +
 packages/dashboard/app/components/QuickChatFAB.css |  17 +-
 packages/dashboard/app/components/QuickChatFAB.tsx |   2 +-
 .../dashboard/app/components/SettingsModal.css     |  11 +-
 .../dashboard/app/components/SettingsModal.tsx     |  22 ++-
 .../dashboard/app/components/TaskDetailModal.css   |  40 +++++
 .../dashboard/app/components/TaskDetailModal.tsx   |  82 +++++++++-
 .../__tests__/SettingsModalNodeRouting.test.tsx    |  12 +-
 .../components/__tests__/TaskDetailModal.test.tsx  |  81 ++++++++-
 packages/engine/src/__tests__/merger.test.ts       |  75 +++++++++
 .../src/__tests__/node-routing-policy.test.ts      |  25 ++-
 .../src/__tests__/scheduler-node-routing.test.ts   |  18 +-
 packages/engine/src/merger.ts                      | 181 +++++++++------------
 packages/engine/src/scheduler.ts                   |   8 +-
 23 files changed, 723 insertions(+), 147 deletions(-)

Fusion-Task-Id: FN-2924

packages/cli/src/commands/__tests__/task.test.ts

@@ -113,6 +113,13 @@ function makeTask(overrides: Record<string, unknown> = {}) {
 describe("runTaskShow", () => {
   let logSpy: ReturnType<typeof vi.spyOn>;
 
+  const mockTaskStoreGetTask = (task: Record<string, unknown>) => {
+    (TaskStore as unknown as ReturnType<typeof vi.fn>).mockImplementation(() => ({
+      init: vi.fn(),
+      getTask: vi.fn().mockResolvedValue(task),
+    }));
+  };
+
   beforeEach(() => {
     logSpy = vi.spyOn(console, "log").mockImplementation(() => {});
   });
@@ -125,10 +132,7 @@ describe("runTaskShow", () => {
     const longDesc = "A".repeat(120); // well over 60 chars
     const task = makeTask({ description: longDesc });
 
-    (TaskStore as unknown as ReturnType<typeof vi.fn>).mockImplementation(() => ({
-      init: vi.fn(),
-      getTask: vi.fn().mockResolvedValue(task),
-    }));
+    mockTaskStoreGetTask(task);
 
     await runTaskShow("FN-001");
 
@@ -148,10 +152,7 @@ describe("runTaskShow", () => {
       description: "This is the full description that should not appear in the header",
     });
 
-    (TaskStore as unknown as ReturnType<typeof vi.fn>).mockImplementation(() => ({
-      init: vi.fn(),
-      getTask: vi.fn().mockResolvedValue(task),
-    }));
+    mockTaskStoreGetTask(task);
 
     await runTaskShow("FN-001");
 
@@ -162,6 +163,33 @@ describe("runTaskShow", () => {
     expect(headerLine![0]).toContain("My Task Title");
     expect(headerLine![0]).not.toContain("This is the full description");
   });
+
+  it.each([
+    [{ sourceType: "dashboard_ui" }, "Source: Dashboard"],
+    [{ sourceType: "agent_heartbeat", sourceAgentId: "agent-123" }, "Source: Agent (agent-123)"],
+    [{ sourceType: "task_refine", sourceParentTaskId: "FN-2904" }, "Source: Refinement of FN-2904"],
+    [{ sourceType: "task_duplicate", sourceParentTaskId: "FN-2905" }, "Source: Duplicate of FN-2905"],
+    [
+      { sourceType: "github_import", sourceMetadata: { issueUrl: "https://github.com/owner/repo/issues/42" } },
+      "Source: GitHub Import (https://github.com/owner/repo/issues/42)",
+    ],
+  ] as const)("prints provenance line for %o", async (overrides, expectedLine) => {
+    mockTaskStoreGetTask(makeTask(overrides));
+
+    await runTaskShow("FN-001");
+
+    const output = logSpy.mock.calls.map((call) => String(call[0])).join("\n");
+    expect(output).toContain(expectedLine);
+  });
+
+  it.each([{ sourceType: "unknown" }, {}])("omits provenance line for %o", async (overrides) => {
+    mockTaskStoreGetTask(makeTask(overrides));
+
+    await runTaskShow("FN-001");
+
+    const output = logSpy.mock.calls.map((call) => String(call[0])).join("\n");
+    expect(output).not.toContain("Source:");
+  });
 });
 
 describe("task node overrides", () => {