feat(clients/windows): screen-module restructure + parity features (speed test, native mode, capture UX)

Structure: split the 1400-line app.rs into per-screen app/ modules (mod=root/
router, hosts, connect, pair, speed, settings, licenses, stream, style) with
shared card/header/busy-page builders and setting_combo/toggle helpers; the
re-render rule (thread-driven state lives in root use_async_state, flows down
as props) is now documented at the module root.

Parity features the other clients already had:
- "Native display" resolves the real monitor mode at connect
  (MonitorFromWindow -> EnumDisplaySettingsW; was a hardcoded 1080p60)
- per-host network speed test: saved-host card button + a results screen
  (probe burst -> goodput/loss -> ~70% recommended bitrate applied in one
  tap; stale runs invalidated by generation) and `--headless --speed-test`;
  the bitrate setting becomes a free-form NumberBox so the recommendation
  round-trips
- forget host (ContentDialog confirm -> KnownHosts::remove_by_fp)
- settings: forwarded-controller picker (pads/pinned/set_pinned now wired),
  gamepad type, host compositor, capture-system-shortcuts; the previously
  dead Settings.compositor / inhibit_shortcuts are honored (shortcuts off =
  Alt+Tab/Alt+Esc/Ctrl+Esc/Win act locally)
- click-to-recapture after a Ctrl+Alt+Shift+Q release; the HUD hint tracks
  the live capture state

Perf: the input hook caches lock geometry (clip rect + contain-fit scale) at
engage instead of GetClientRect per WM_MOUSEMOVE; the audio jitter ring trims
via drain() and reuses the render scratch buffer.

Validated on the bare-metal box: --discover, synthetic-host loopback E2E
(TOFU -> clock skew -> HEVC negotiate -> D3D11VA init -> session end),
speed-test E2E, and the WinUI shell rendering in the console session via
PsExec (SSH/session-0 cannot create windows, pre-existing 0x80070005).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

clients/windows/src/trust.rs

@@ -84,14 +84,16 @@ impl KnownHosts {
         Ok(())
     }
 
-    // Used by the GUI host-list's pinned-fingerprint trust decision (the silent-reconnect
-    // path); the current CLI trust flow keys on address. Kept for parity with the other
-    // clients' known-hosts API — wired when the discovered-hosts UI lands.
-    #[allow(dead_code)]
     pub fn find_by_fp(&self, fp_hex: &str) -> Option<&KnownHost> {
         self.hosts.iter().find(|h| h.fp_hex == fp_hex)
     }
 
+    /// Forget a host (the hosts page's "Forget" action): drops the pinned fingerprint, so a
+    /// later connect goes back through pairing/TOFU.
+    pub fn remove_by_fp(&mut self, fp_hex: &str) {
+        self.hosts.retain(|h| h.fp_hex != fp_hex);
+    }
+
     pub fn find_by_addr(&self, addr: &str, port: u16) -> Option<&KnownHost> {
         self.hosts.iter().find(|h| h.addr == addr && h.port == port)
     }