fix(shell): never step a stored out-of-range zoom level against the request

A level persisted before the shortcuts existed (the macOS menu roles never
clamped, and the store restores any finite level) was clamped BEFORE the
step, so the first zoom-in from level 7 rendered smaller. Step from the raw
level instead: a press further out leaves an out-of-range level where it is,
a press back in lands on the limit.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

docs/architecture/workspace-shell.md

@@ -473,7 +473,10 @@ Zoom level (Cmd/Ctrl and +/−/0, issue #1109):
    (`stepZoomLevel`): 0.5 per press, Electron's own `zoomIn`/`zoomOut` role
    step (≈10 %), clamped to levels −4…6 (≈48 %…299 %, inside Chromium's
    25–500 %), off-grid levels snapping to the next grid point in the pressed
-   direction; `Ctrl/Cmd+0` returns to level 0. Persistence needs nothing
+   direction; `Ctrl/Cmd+0` returns to level 0. A stored level already
+   outside the limits (the macOS menu roles never clamped) is never moved
+   against the request: a press further out leaves it, a press back in
+   lands on the limit. Persistence needs nothing
    extra: the main process reads the live level back (point 3). On macOS the
    default application menu still carries the `zoomIn`/`zoomOut`/`resetZoom`
    roles, but Chromium hands a key equivalent to the web contents first and

libs/shared/interfaces/src/lib/zoom-level.util.spec.ts

@@ -23,13 +23,25 @@ describe('zoom level shortcuts contract', () => {
     it('clamps at the app limits, not at Chromium limits', () => {
         expect(stepZoomLevel(ZOOM_LEVEL_MAX, 'in')).toBe(ZOOM_LEVEL_MAX);
         expect(stepZoomLevel(ZOOM_LEVEL_MIN, 'out')).toBe(ZOOM_LEVEL_MIN);
-        expect(stepZoomLevel(ZOOM_LEVEL_MAX + 3, 'in')).toBe(ZOOM_LEVEL_MAX);
-        expect(stepZoomLevel(ZOOM_LEVEL_MAX + 3, 'out')).toBe(
-            ZOOM_LEVEL_MAX - ZOOM_LEVEL_STEP
-        );
+        expect(stepZoomLevel(ZOOM_LEVEL_MAX - 0.5, 'in')).toBe(ZOOM_LEVEL_MAX);
         expect(clampZoomLevel(ZOOM_LEVEL_MIN - 1)).toBe(ZOOM_LEVEL_MIN);
     });
 
+    it('never moves a stored out-of-range level against the request', () => {
+        // The macOS menu roles never clamped and the store restores any
+        // finite level, so an upgrade can start beyond the limits.
+        expect(stepZoomLevel(ZOOM_LEVEL_MAX + 1, 'in')).toBe(
+            ZOOM_LEVEL_MAX + 1
+        );
+        expect(stepZoomLevel(ZOOM_LEVEL_MAX + 1, 'out')).toBe(ZOOM_LEVEL_MAX);
+        expect(stepZoomLevel(ZOOM_LEVEL_MAX + 0.3, 'out')).toBe(ZOOM_LEVEL_MAX);
+        expect(stepZoomLevel(ZOOM_LEVEL_MIN - 1, 'out')).toBe(
+            ZOOM_LEVEL_MIN - 1
+        );
+        expect(stepZoomLevel(ZOOM_LEVEL_MIN - 1, 'in')).toBe(ZOOM_LEVEL_MIN);
+        expect(stepZoomLevel(ZOOM_LEVEL_MIN - 1, 'reset')).toBe(0);
+    });
+
     it('snaps an off-grid level to the next grid point in the requested direction', () => {
         // A level the macOS menu roles or an older store left between steps.
         expect(stepZoomLevel(0.3, 'in')).toBe(0.5);

libs/shared/interfaces/src/lib/zoom-level.util.ts

@@ -33,7 +33,10 @@ export function clampZoomLevel(level: number): number {
  * The level `action` produces from `current`. Steps are snapped to the step
  * grid so a level restored from an older store (or set by the macOS menu
  * before the shortcuts existed) does not carry a fractional offset forever.
- * A non-finite `current` is treated as the default.
+ * A level already outside the limits — the macOS menu roles never clamped,
+ * and the store restores any finite level — is never moved AGAINST the
+ * request: a press further out leaves it where it is, a press back in lands
+ * on the limit. A non-finite `current` is treated as the default.
  */
 export function stepZoomLevel(
     current: number,
@@ -43,8 +46,13 @@ export function stepZoomLevel(
         return ZOOM_LEVEL_DEFAULT;
     }
 
-    const base = clampZoomLevel(current);
+    const base = Number.isFinite(current) ? current : ZOOM_LEVEL_DEFAULT;
     const direction = action === 'in' ? 1 : -1;
+
+    if (direction > 0 ? base >= ZOOM_LEVEL_MAX : base <= ZOOM_LEVEL_MIN) {
+        return base;
+    }
+
     const steps = base / ZOOM_LEVEL_STEP;
     // A level between grid points steps to the next grid point in the
     // requested direction instead of skipping past it.
@@ -53,7 +61,6 @@ export function stepZoomLevel(
         : direction > 0
           ? Math.ceil(steps)
           : Math.floor(steps);
-    const next = nextSteps * ZOOM_LEVEL_STEP;
 
-    return clampZoomLevel(next);
+    return clampZoomLevel(nextSteps * ZOOM_LEVEL_STEP);
 }