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/vite-env.d.ts

@@ -1 +1,9 @@
 /// <reference types="vite/client" />
+
+declare global {
+  interface Window {
+    __psyHidden?: boolean;
+  }
+}
+
+export {};