test(mobile): declare per-view mobile treatment and harden the visual gate (#1332)

* test(mobile): single-source map for per-view mobile treatment

Declare how every top-level view behaves on a phone in one place:
MOBILE_TREATMENTS is a Record<ActiveView, ...>, so adding a new view without
classifying it (bespoke / responsive / desktop-only / detail) fails the type
check. BESPOKE_MOBILE_VIEWS is derived from it instead of hand-maintained, and
a unit test keeps the two in lockstep and pins the current bespoke set so a
change is deliberate. EditorLayout consumes the derived set; behavior is
unchanged.

* ci(visual): run the desktop-unchanged gate in its own job

Split the visual-regression spec into a dedicated Playwright "visual" project,
excluded from the default chromium project the functional E2E job runs, so a
missing or platform-mismatched baseline can no longer fail every PR.

Add a Visual Regression workflow: a compare job gates PRs into main against
committed baselines (and skips with a warning until they are seeded), and a
manual seed job regenerates the baselines on the Linux runner and commits them
to a feature branch (refusing main). Baselines are platform-specific, so they
must be produced on the runner rather than locally.

Drop the stack-detail view from the gate: a fresh CI app has no stack to open
and its live log stream is not deterministic; the shell plus the four content
views still catch a desktop base-class regression.

frontend/src/components/EditorLayout/mobile-treatments.test.ts

@@ -0,0 +1,32 @@
+import { describe, it, expect } from 'vitest';
+import { MOBILE_TREATMENTS, BESPOKE_MOBILE_VIEWS, type MobileTreatment } from './mobile-treatments';
+
+const VALID: MobileTreatment[] = ['bespoke', 'responsive', 'desktop-only', 'detail'];
+
+describe('mobile treatments', () => {
+  it('classifies every view with a known treatment', () => {
+    // The Record<ActiveView, MobileTreatment> type already forces every view to
+    // be present at compile time; this guards the values at runtime so a typo or
+    // a bad merge cannot leave an unknown treatment in the map.
+    for (const [view, treatment] of Object.entries(MOBILE_TREATMENTS)) {
+      expect(VALID, `${view} has an unknown treatment "${treatment}"`).toContain(treatment);
+    }
+  });
+
+  it('keeps BESPOKE_MOBILE_VIEWS in lockstep with the bespoke treatments', () => {
+    const declaredBespoke = Object.entries(MOBILE_TREATMENTS)
+      .filter(([, treatment]) => treatment === 'bespoke')
+      .map(([view]) => view)
+      .sort();
+    expect([...BESPOKE_MOBILE_VIEWS].sort()).toEqual(declaredBespoke);
+  });
+
+  it('pins the set of bespoke phone screens (update deliberately when adding one)', () => {
+    // A change here means a top-level view gained or lost a bespoke phone screen.
+    // Updating this list should go hand in hand with adding the screen under
+    // components/mobile/ and wiring its case in EditorLayout's renderMobileBespoke.
+    expect([...BESPOKE_MOBILE_VIEWS].sort()).toEqual(
+      ['dashboard', 'fleet', 'scheduled-ops', 'settings'],
+    );
+  });
+});