FN-7922: fix jerky tablet drag on headerless floating-window handles

Ensures every draggable modal surface (terminal, artifacts viewer, and other
FloatingWindow delegates) keeps touch-action: none on its drag handle so
tablet touch-drag is captured by FloatingWindow's pointermove stream instead
of being intersected by page pan, and backs the contract with tests.

- Add touch-action: none to .artifacts-gallery-viewer-header, the headerless
  FloatingWindow's delegated drag handle, matching the other movable modal
  handles.
- Add a FloatingWindow test asserting touch-action: none is present across
  every tablet movable-modal drag handle (terminal, artifacts, workflow
  editor, automation, mission interview, PR create, file browser, right
  dock, new task modal, quick chat FAB) and absent from broad tablet
  pan-y overrides.
- Add a FloatingWindow test exercising the captured tablet touch-drag path
  for a headerless delegated handle (pointerdown/move/up with
  pointerType: "touch").
- Fix TerminalModal drag test to send pointerType: "touch" on
  pointerdown/move/up so it exercises the same tablet touch-drag contract.
- Add changeset for the tablet drag fix.

Files changed:
 .changeset/fn-7922-tablet-modal-drag.md            |  7 ++
 .../dashboard/app/components/ArtifactsGallery.css  |  5 ++
 .../components/__tests__/FloatingWindow.test.tsx   | 76 +++++++++++++++++++++-
 .../components/__tests__/TerminalModal.test.tsx    |  6 +-
 4 files changed, 90 insertions(+), 4 deletions(-)

Fusion-Task-Id: FN-7922

Fusion-Task-Lineage: 0d63ced5-faa7-4362-a42d-884b4c889ebf

Co-authored-by: Fusion (runfusion.ai) <noreply@runfusion.ai>

.changeset/fn-7922-tablet-modal-drag.md

@@ -0,0 +1,7 @@
+---
+"@runfusion/fusion": patch
+---
+
+summary: Fix jerky tablet drag for the terminal and other movable modals.
+category: fix
+dev: Reassert drag-handle `touch-action: none` coverage for headerless floating-window delegates and test the tablet touch-drag contract across movable modal surfaces.

packages/dashboard/app/components/ArtifactsGallery.css

@@ -369,11 +369,16 @@ Viewers live inside the shared FloatingWindow (draggable by the viewer header, r
   padding: var(--space-md);
 }
 
+/*
+FNXC:ArtifactsGallery 2026-07-12-21:10:
+The artifacts viewer is a headerless FloatingWindow, so this header is the delegated drag handle on tablet and coarse-pointer floating layouts. Keep its effective `touch-action: none` so a single-finger drag is delivered through FloatingWindow's captured pointermove stream instead of being intersected back into page pan; the mobile sheet override below still disables the desktop drag affordance at <=768px.
+*/
 .artifacts-gallery-viewer-header {
   display: flex;
   align-items: center;
   gap: var(--space-sm);
   cursor: grab;
+  touch-action: none;
 }
 
 .artifacts-gallery-viewer-header:active {

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

@@ -1,11 +1,12 @@
 import { render, screen, fireEvent } from "@testing-library/react";
 import { readFileSync } from "node:fs";
 import { beforeEach, describe, expect, it, vi } from "vitest";
-import { loadAllAppCss } from "../../test/cssFixture";
+import { loadAllAppCss, loadStylesCss } from "../../test/cssFixture";
 import { FloatingWindow } from "../FloatingWindow";
 
 const floatingWindowCss = readFileSync("app/components/FloatingWindow.css", "utf8");
 const allAppCss = loadAllAppCss();
+const stylesCss = loadStylesCss();
 
 function cssRuleFor(css: string, selector: string): string {
   const start = css.indexOf(`${selector} {`);
@@ -14,6 +15,15 @@ function cssRuleFor(css: string, selector: string): string {
   return css.slice(start, end);
 }
 
+function cssRuleContaining(css: string, selector: string, declaration: string): string {
+  const escaped = selector.replace(/[.*+?^${}()|[\]\\]/g, "\\$&").replace(/\\ /g, "\\s+");
+  const matches = css.matchAll(new RegExp(`${escaped}\\s*\\{[^}]*\\}`, "g"));
+  for (const match of matches) {
+    if (match[0].includes(declaration)) return match[0];
+  }
+  return "";
+}
+
 /*
 FNXC:FloatingWindow 2026-06-22-20:45:
 Contract tests for the reusable non-blocking floating window:
@@ -83,6 +93,35 @@ describe("FloatingWindow", () => {
     }
   });
 
+  it("keeps every tablet movable-modal drag handle on the explicit touch-action none contract", () => {
+    const tabletStylesStart = stylesCss.indexOf("@media (min-width: 769px) and (max-width: 1024px)");
+    const mobileStylesStart = stylesCss.indexOf("@media (max-width: 768px)", tabletStylesStart);
+    expect(tabletStylesStart).toBeGreaterThan(-1);
+    expect(mobileStylesStart).toBeGreaterThan(tabletStylesStart);
+
+    const tabletBlock = stylesCss.slice(tabletStylesStart, mobileStylesStart);
+    expect(tabletBlock).not.toContain("* {");
+    expect(tabletBlock).not.toContain("touch-action: pan-y;");
+
+    for (const selector of [
+      ".floating-window__header",
+      ".floating-window--headerless .task-detail-content--embedded > .modal-header",
+      ".chat-view--floating .view-header",
+      ".floating-window--workflow-editor .wf-editor-header",
+      ".floating-window--automation .automation-modal__drag-handle",
+      ".floating-window--mission-interview .mission-interview-modal__drag-handle",
+      ".floating-window--pr-create .pr-create-modal__drag-handle",
+      ".file-browser-modal-header",
+      ".artifacts-gallery-viewer-header",
+      ".terminal-header--draggable",
+      ".right-dock-expand-modal__header--draggable",
+      ".new-task-modal__header--draggable",
+      ".quick-chat-fab",
+    ]) {
+      expect(cssRuleContaining(allAppCss, selector, "touch-action: none;"), selector).toContain("touch-action: none;");
+    }
+  });
+
   it("moves a visible-header window through the captured touch drag path", () => {
     render(
       <FloatingWindow
@@ -141,6 +180,41 @@ describe("FloatingWindow", () => {
     }
   });
 
+  it("moves a headerless delegated handle through the captured tablet touch drag path", () => {
+    render(
+      <FloatingWindow
+        windowKey="artifacts-delegate"
+        title="Artifacts"
+        onClose={() => {}}
+        hideHeader
+        dragHandleSelector=".artifacts-gallery-viewer-header"
+        className="artifacts-gallery-window"
+        defaultSize={{ width: 320, height: 240 }}
+        defaultPosition={{ x: 90, y: 110 }}
+        minSize={{ width: 240, height: 180 }}
+      >
+        <div className="artifacts-gallery-viewer-header">Artifacts header</div>
+        <div aria-label="empty artifacts body" />
+      </FloatingWindow>
+    );
+
+    const panel = screen.getByTestId("floating-window-artifacts-delegate");
+    const delegatedHeader = screen.getByText("Artifacts header");
+    const setPointerCapture = vi.fn();
+    const releasePointerCapture = vi.fn();
+    Object.defineProperty(panel, "setPointerCapture", { configurable: true, value: setPointerCapture });
+    Object.defineProperty(panel, "releasePointerCapture", { configurable: true, value: releasePointerCapture });
+
+    fireEvent.pointerDown(delegatedHeader, { pointerId: 23, pointerType: "touch", clientX: 120, clientY: 140 });
+    fireEvent.pointerMove(panel, { pointerId: 23, pointerType: "touch", clientX: 150, clientY: 170 });
+    fireEvent.pointerUp(panel, { pointerId: 23, pointerType: "touch", clientX: 150, clientY: 170 });
+
+    expect(setPointerCapture).toHaveBeenCalledWith(23);
+    expect(releasePointerCapture).toHaveBeenCalledWith(23);
+    expect(panel.style.left).toBe("120px");
+    expect(panel.style.top).toBe("140px");
+  });
+
   it("scopes mobile sheet sizing and hidden resize handles to task-detail pop-outs", () => {
     expect(floatingWindowCss).toContain("FNXC:MobileTaskPopups 2026-06-29-00:00");
     expect(floatingWindowCss).toContain(".floating-window--task-detail {");

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

@@ -1089,9 +1089,9 @@ describe("TerminalModal", () => {
     const header = modal.querySelector(".terminal-header") as HTMLElement & { setPointerCapture: (pointerId: number) => void; releasePointerCapture: (pointerId: number) => void };
     header.setPointerCapture = vi.fn();
     header.releasePointerCapture = vi.fn();
-    fireEvent.pointerDown(header, { pointerId: 2, clientX: 100, clientY: 100 });
+    fireEvent.pointerDown(header, { pointerId: 2, pointerType: "touch", clientX: 100, clientY: 100 });
-    fireEvent.pointerMove(header, { pointerId: 2, clientX: 125, clientY: 135 });
+    fireEvent.pointerMove(header, { pointerId: 2, pointerType: "touch", clientX: 125, clientY: 135 });
-    fireEvent.pointerUp(header, { pointerId: 2 });
+    fireEvent.pointerUp(header, { pointerId: 2, pointerType: "touch" });
 
     await waitFor(() => {
       expect(window.localStorage.getItem(`fusion:terminal-float-pos-${projectId}`)).toBeTruthy();