fix(desktop): keep preview zoom independent

apps/desktop/src/preview/WebviewPreferences.test.ts

@@ -43,21 +43,25 @@ function parseWebPreferences(input: string): Record<string, unknown> {
 describe("PREVIEW_WEBVIEW_PREFERENCES", () => {
   const parsed = parseWebPreferences(PREVIEW_WEBVIEW_PREFERENCES);
 
-  it("contains exactly the three security-critical keys", () => {
+  it("contains only the required preview overrides", () => {
     expect(Object.keys(parsed).toSorted()).toEqual(
-      ["contextIsolation", "nodeIntegration", "sandbox"].toSorted(),
+      ["contextIsolation", "nodeIntegration", "sandbox", "zoomFactor"].toSorted(),
     );
   });
 
   it("uses canonical JS-boolean string literals (not yes/no, on/off, 1/0)", () => {
     // `value="no"` is a TRUTHY string when assigned to webPreferences.X — so
     // `contextIsolation="no"` would silently leave isolation ENABLED. Lock
     // the values to `"true"` / `"false"` so the parser does the right thing.
-    for (const value of Object.values(parsed)) {
-      expect(value).toMatch(/^(true|false)$/);
+    for (const key of ["contextIsolation", "nodeIntegration", "sandbox"]) {
+      expect(parsed[key]).toMatch(/^(true|false)$/);
     }
   });
 
+  it("starts previews at 100% independently of the app zoom", () => {
+    expect(parsed["zoomFactor"]).toBe("1");
+  });
+
   it("disables context isolation (so react-grab can see the page's React DevTools hook)", () => {
     expect(parsed["contextIsolation"]).toBe("false");
   });

apps/desktop/src/preview/WebviewPreferences.ts

@@ -21,13 +21,15 @@
  *   the preload's `import { ipcRenderer }` line, but no Node globals leak.
  * - `nodeIntegration=false`: pinned for clarity (the page itself never gets
  *   Node access).
+ * - `zoomFactor=1`: Electron otherwise initializes each guest with the
+ *   embedder's current zoom, coupling a newly-opened preview to the app UI.
  *
  * Format notes (locked down by `WebviewPreferences.test.ts`):
  * - Whitespace-free. Electron's webpreferences parser splits on `,` and
  *   does not trim, so a leading space would turn a key into an unknown one
  *   and silently drop it.
- * - Values are JS-boolean strings (`true`/`false`) — `yes`/`no` are not
- *   special-cased by the parser; `value="no"` becomes the truthy STRING
+ * - Boolean values use JS-boolean strings (`true`/`false`) — `yes`/`no` are
+ *   not special-cased by the parser; `value="no"` becomes the truthy STRING
  *   `"no"` when assigned to a boolean webPreferences key. Most critically,
  *   `contextIsolation="no"` is truthy → contextIsolation stays ENABLED →
  *   react-grab can't see the React DevTools hook.
@@ -39,4 +41,4 @@
  * security-critical flags can't regress on preview tabs.
  */
 export const PREVIEW_WEBVIEW_PREFERENCES =
-  "contextIsolation=false,sandbox=true,nodeIntegration=false";
+  "contextIsolation=false,sandbox=true,nodeIntegration=false,zoomFactor=1";

docs/user/keybindings.md

@@ -55,6 +55,9 @@ characters and uses SQLite's ASCII case-insensitive matching.
 The full command list and the current defaults are shown in **Settings** → **Keybindings**, which
 always matches the build you are running. Use that rather than a copied list.
 
+On desktop, app UI zoom and integrated-browser zoom are independent. New browser previews start at
+100%, and the preview's three-dot menu changes only that browser tab's zoom.
+
 Note that `chat.new` and `chat.newLocal` both create a thread through the same path. A new thread
 inherits the project you were in, along with model and mode selections. Branch, worktree, and
 environment mode always come from your configured defaults, not from the thread you were looking