Add iOS WebRTC input and streamer reconnect capability

[Kief5555]

This PR implements WebRTC DataChannel-based touch/keyboard input using the desktop binary protocol and introduces the ability to reopen the streamer after closing it via the QueueStatusPill.

StreamerView.swift:

• Created reliable and partially reliable input DataChannels before setRemoteDescription.
• Implemented protocol v2 binary encoders (encodeHeartbeat, encodeKey, encodeMouseMove, encodeMouseButton) with microsecond timestamps.
• Added touch overlay for relative mouse movement, single-tap left click, and two-finger right click.
• Added on-screen keyboard bar with Windows VK/scancode mapping for character input.
• Added input heartbeat interval and proper channel cleanup on signaling close.

OpenNOWStore.swift:

• Added canReopenStreamer computed property to verify session readiness (status 2 or 3).
• Added reopenStreamer() function to restore streamSession from activeSession.

ContentView.swift:

• Updated QueueStatusPill subtitle to show "Tap to return" when session is ready but streamSession is nil.
• Updated pill button action to call reopenStreamer() when available instead of maximizing the queue overlay.