feat(FN-3631): replicate task creation across mesh nodes and fix modal scrolling

- Add mesh task replication plumbing in core store/types with node-aware task creation metadata
- Expose dashboard and mesh API route coverage for replicated task creation and sync behavior
- Restore independent scrolling in Git Manager changes list and prevent Scripts modal scroll regressions
- Expand tests across core, dashboard routes, API, and CLI extension insights for the new behavior

Fusion-Task-Id: FN-3631

packages/dashboard/app/components/GitManagerModal.tsx

@@ -1117,7 +1117,7 @@ function ChangesPanel({
             )}
           </div>
         </div>
-        <div className="gm-file-list">
+        <div className="gm-file-list gm-file-list-unstaged" data-testid="gm-file-list-unstaged">
           {unstagedFiles.length === 0 ? (
             <div className="gm-empty">No unstaged changes</div>
           ) : (
@@ -1189,7 +1189,7 @@ function ChangesPanel({
             )}
           </div>
         </div>
-        <div className="gm-file-list">
+        <div className="gm-file-list gm-file-list-staged" data-testid="gm-file-list-staged">
           {stagedFiles.length === 0 ? (
             <div className="gm-empty">No staged changes</div>
           ) : (

packages/dashboard/app/components/ScriptsModal.css

@@ -2058,6 +2058,7 @@
   position: sticky;
   top: 0;
   align-self: start;
+  min-height: 0;
   /* Cap the sticky column so its internal lists never push past the viewport
    * — without this, two long lists at max-height 200px each + headers can
    * exceed the available scroll-port height and the column visually clips. */
@@ -2118,6 +2119,9 @@
 /* ── File Section ── */
 
 .gm-file-section {
+  display: flex;
+  flex-direction: column;
+  min-height: 0;
   border: 1px solid var(--border);
   border-radius: var(--radius-md);
   overflow: hidden;
@@ -2149,8 +2153,11 @@
 /* ── File List ── */
 
 .gm-file-list {
-  max-height: 200px;
+  min-height: 0;
+  max-height: calc(var(--space-2xl) * 6 + var(--space-md));
   overflow-y: auto;
+  overscroll-behavior: contain;
+  -webkit-overflow-scrolling: touch;
 }
 
 .gm-file-item {

packages/dashboard/app/components/__tests__/GitManagerModal.test.tsx

@@ -420,6 +420,35 @@ describe("GitManagerModal", () => {
     });
   });
 
+  it("keeps separate scroll containers for unstaged and staged file lists", async () => {
+    (fetchFileChanges as any).mockResolvedValue([
+      ...Array.from({ length: 30 }, (_, index) => ({
+        file: `src/unstaged-${index}.ts`,
+        status: "modified",
+        staged: false,
+      })),
+      { file: "src/staged.ts", status: "added", staged: true },
+    ]);
+
+    render(
+      <GitManagerModal isOpen={true} onClose={vi.fn()} tasks={mockTasks} addToast={mockAddToast} />
+    );
+    fireEvent.click(screen.getByRole("tab", { name: /changes/i }));
+
+    await waitFor(() => {
+      expect(screen.getByText("Unstaged Changes (30)")).toBeInTheDocument();
+      expect(screen.getByText("Staged Changes (1)")).toBeInTheDocument();
+    });
+
+    const unstagedList = screen.getByTestId("gm-file-list-unstaged");
+    const stagedList = screen.getByTestId("gm-file-list-staged");
+
+    expect(unstagedList).toHaveClass("gm-file-list", "gm-file-list-unstaged");
+    expect(stagedList).toHaveClass("gm-file-list", "gm-file-list-staged");
+    expect(within(unstagedList).getAllByRole("button").length).toBeGreaterThan(10);
+    expect(within(stagedList).getAllByRole("button").length).toBeGreaterThan(0);
+  });
+
   it("stages all files when Stage All is clicked", async () => {
     const user = userEvent.setup();
     render(

packages/dashboard/app/components/__tests__/core-modals-mobile.test.tsx

@@ -193,6 +193,22 @@ describe("core modals mobile css coverage", () => {
     expect(fileSectionRule![0]).toContain("max-width: 100%");
   });
 
+  it("GitManagerModal: file sections and file lists keep independent scrolling constraints", () => {
+    const css = loadAllAppCss();
+
+    const fileSectionRule = css.match(/\.gm-file-section\s*\{[^}]+\}/s);
+    expect(fileSectionRule).not.toBeNull();
+    expect(fileSectionRule![0]).toContain("display: flex");
+    expect(fileSectionRule![0]).toContain("flex-direction: column");
+    expect(fileSectionRule![0]).toContain("min-height: 0");
+
+    const fileListRule = css.match(/\.gm-file-list\s*\{[^}]+\}/s);
+    expect(fileListRule).not.toBeNull();
+    expect(fileListRule![0]).toContain("overflow-y: auto");
+    expect(fileListRule![0]).toContain("overscroll-behavior: contain");
+    expect(fileListRule![0]).toContain("-webkit-overflow-scrolling: touch");
+  });
+
   it("GitManagerModal: modal uses full-screen viewport sizing on mobile (641-768px range)", () => {
     const css = loadAllAppCss();
     const mobileBlock = getMainMobileBlock(css);