fix(apple/iOS): capture all attached mice; gate UIKit pointer path under lock

The iPad pointer lock engaged but a Magic Keyboard trackpad went dead the
moment a second pointer (a Universal Control "V-UC Automouse") was connected —
on-device PUNKTFUNK_INPUT_DEBUG logs showed only ONE GCMouse attached (whichever
was GCMouse.current), so the other device's motion handler was never installed.

InputCapture.start() now attaches a handler to EVERY GCMouse.mice(), not just
GCMouse.current, so a trackpad and a second mouse both drive (each GCMouse
delivers its own deltas through its own handler). New arrivals still come via the
GCMouseDidConnect observer.

Also gate the WHOLE UIKit indirect-pointer path (motion, buttons AND scroll) on
!gcMouseForwarding, not just motion+scroll: under pointer lock GCMouse owns
buttons too, and the trackpad/mouse also emit UIKit indirect-pointer events
pinned at the locked position — without the gate a click double-sent (GCMouse +
UIKit). The two paths are now exact mirrors on `gcMouseForwarding` (== locked).

Removes the investigation-only diagnostics (attachedMiceSummary/hasGCMouse, the
per-event UIKit pointer/scroll logs, the GCMouse attach/became-current logs);
the pre-existing `pointer lock isLocked=… captured=…` debug line is restored.

iOS compiles against the SDK; macOS swift build + test green (49 tests).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

clients/apple/Sources/PunktfunkKit/InputCapture.swift

@@ -107,23 +107,6 @@ public final class InputCapture {
     /// macOS (no GCMouse handlers installed; `sendMouseAbs` is never called there). Main-queue.
     public var gcMouseForwarding = false
 
-    #if os(iOS)
-    /// Whether any device is attached as a `GCMouse` right now. The Magic Keyboard TRACKPAD does
-    /// not always register as a GCMouse on iPadOS (only a standalone mouse does) — when no GCMouse
-    /// is present the relative GCMouse path can't carry pointer motion. Main-queue.
-    public var hasGCMouse: Bool { !mice.isEmpty }
-
-    /// Diagnostic: a one-line description of every attached GCMouse (count + GCDevice identity), so
-    /// PUNKTFUNK_INPUT_DEBUG can reveal whether the trackpad showed up as a mouse at all.
-    public var attachedMiceSummary: String {
-        guard !mice.isEmpty else { return "0 mice" }
-        let parts = mice.map { mouse -> String in
-            "\(mouse.productCategory)/\(mouse.vendorName ?? "?")"
-        }
-        return "\(mice.count) mice: \(parts.joined(separator: ", "))"
-    }
-    #endif
-
     /// Fired on ⌘⎋ (the capture toggle — detected here so it works in both states; the
     /// event itself is swallowed). Main queue.
     public var onToggleCapture: (() -> Void)?
@@ -177,7 +160,13 @@ public final class InputCapture {
             previous.onPreempted?()
         }
         Self.activeCapture = self
-        if let mouse = GCMouse.current { attach(mouse: mouse) }
+        // Attach EVERY connected mouse, not just GCMouse.current. With two pointing devices (e.g.
+        // the iPad's own Magic Keyboard trackpad AND a Universal Control "V-UC Automouse"), only one
+        // is `current` at a time; attaching just that one left the OTHER device's motion handler
+        // uninstalled, so moving it did nothing. Each GCMouse delivers its own deltas through its own
+        // handler, so handling all of them lets either device drive. New arrivals are caught by the
+        // GCMouseDidConnect observer below.
+        for mouse in GCMouse.mice() { attach(mouse: mouse) }
         if let keyboard = GCKeyboard.coalesced { attach(keyboard: keyboard) }
         observers.append(NotificationCenter.default.addObserver(
             forName: .GCMouseDidConnect, object: nil, queue: .main
@@ -411,12 +400,6 @@ public final class InputCapture {
               !mice.contains(where: { $0 === mouse }) // re-delivered on wake — attach once
         else { return }
         mice.append(mouse)
-        #if os(iOS)
-        if inputDebug {
-            inputLog.debug(
-                "GCMouse attached: \(mouse.productCategory, privacy: .public)/\(mouse.vendorName ?? "?", privacy: .public) — now \(self.attachedMiceSummary, privacy: .public)")
-        }
-        #endif
         // macOS drives motion + buttons from NSEvent (StreamLayerView's local monitor →
         // sendMotion/sendMouseButton) because GCMouse's handlers proved unreliable there;
         // installing them too would double-send. iOS keeps GCMouse (raw deltas under