feat(client): cross-target input handling + LAN mDNS discovery

Input handling, building on macOS/iOS/tvOS:
- macOS recapture after navigating out: engageCapture no longer latches
  captured=true when the cursor grab is refused mid app-activation (which left
  a free cursor that no later click could re-grab); cursorCapture.capture() now
  reports success. + canBecomeKeyView.
- iOS/iPadOS recapture: restore the prior capture on didBecomeActive (nothing
  re-grabbed mouse/keyboard on return before).
- iPad indirect pointer (no lock) is forwarded as an absolute MOUSE (move +
  buttons + scroll via hover / UITouch.indirectPointer), not as touch, with the
  local cursor visible; GCMouse owns the locked regime, gated so the two never
  double-send. Adds the MouseMoveAbs wire helper.
- Trackpad scroll on iOS (was entirely missing): GCMouse scroll dpad when
  locked + a scroll-only UIPanGestureRecognizer otherwise.
- tvOS: no focusable control during play (a focusable Disconnect button ate the
  controller's A in the focus engine); Siri Remote Menu disconnects.
- Don't leak touch to the host under the TOFU trust prompt (gate on
  captureEnabled).

LAN discovery: HostDiscovery (NWBrowser over _punktfunk._udp, the host's
crate::discovery advert) resolves each service to IP:port and parses the TXT
(fp advisory, pair, id); an "On this network" section in the grid (tap to save
+ connect, or pair if required). iOS/tvOS get NSBonjourServices via a merged
Config/Info.plist. Integration-tested end to end against a fake NWListener advert.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

clients/apple/Config/Info.plist

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<!-- Custom keys merged into the auto-generated Info.plist (GENERATE_INFOPLIST_FILE=YES
+	     supplies the rest). NSBonjourServices is required for NWBrowser to browse this
+	     service type on iOS/tvOS — without it the system blocks the browse and discovery
+	     returns nothing. Kept OUT of the synchronized App/ + Sources/ groups so it isn't
+	     auto-added as a bundle resource (which collides with Info.plist processing). -->
+	<key>NSBonjourServices</key>
+	<array>
+		<string>_punktfunk._udp</string>
+	</array>
+</dict>
+</plist>