fix(windows): tighten WebView2 idle hooks from #273 review (#276)

- Type `window.__psyHidden` once via global declaration; drop 6 `(window as any)` casts.
- `WindowVisibilityProvider` now ORs `window.__psyHidden` into the hidden state
  (and into the initial state). On WebView2 `document.hidden` does not always
  flip when `win.hide()` is called, so effects gated by `useWindowVisibility()`
  can now actually skip creating intervals/rAF instead of relying solely on the
  per-tick fallback check.
- Slow visible-poll from 200 ms to 500 ms (5 → 2 wakeups/s for visibility alone).
- Fix stray leading-space indent in `App.tsx` `window:close-requested` comment.

Co-authored-by: Psychotoxical <dev@psysonic.app>

src/App.tsx

@@ -931,7 +931,7 @@ function TauriEventBridge() {
         unlisten.push(u);
       }
 
-     // window:close-requested is emitted by Rust (prevent_close + emit).
+      // window:close-requested is emitted by Rust (prevent_close + emit).
       // JS decides: minimize to tray or exit, based on user setting.
       const u = await listen('window:close-requested', async () => {
         if (useAuthStore.getState().minimizeToTray) {