feat(apple): add native macOS and iOS clients

[oleksoleksoleks]

Summary

• add native SwiftUI macOS and iOS clients with shared protocol, client, platform, and UI modules
• make macOS connect automatically to the local OMP appserver over a Unix-domain WebSocket
• bundle and supervise compatible local omp and t4-host runtimes while keeping Tailnet hosts optional

Screenshots

No screenshots attached.

Testing

• cd apps/apple && swift test — 23 tests passed
• cd apps/apple && T4_LIVE_LOCAL_HOST=1 swift test --filter LiveLocalHostTests — local handshake, negotiation, session listing, and bootstrap passed during implementation
• cd apps/apple && xcodebuild -project T4AppleApps.xcodeproj -scheme T4MacApp -configuration Debug CODE_SIGNING_ALLOWED=NO build
• launched the resulting T4MacApp.app and confirmed its bundled T4Runtime/omp and T4Runtime/t4-host

Risk

• large new platform surface; macOS local-host startup depends on the staged runtime matching the current appserver protocol
• iOS remains remote-host only because Unix-domain local host supervision is macOS-specific

Notes

• DEVPOST.md remains untracked and is not included

AI Review Report

• verified local runtime ownership rules: the app only terminates processes it launched and does not claim an already healthy socket
• verified feature-gated host.watch, bounded protocol decoding, masked WebSocket frames, and reconnect generation handling

Security Audit

• validates bundled executables as regular, executable, non-symlink resources
• bounds frame sizes, JSON depth/node counts, diagnostics, and startup wait time
• does not pass remote networking flags to the local host process