Merges external Tailscale funnel detection (FN-2976) — adds types, detection logic, status inclusion, kill flow, and a dedicated UI panel for funnel processes started outside Fusion — alongside custom AI providers API routes and a new settings UI section (FN-2965).
Fusion-Task-Id: FN-2976
- Add docs/remote-access.md as the canonical runbook for dashboard, TUI, and headless remote access operations
- Document provider prerequisites, lifecycle restore gates, and status/diagnostic semantics for remote tunnel management
- Add remote auth security guidance for tokenized URLs/QR payloads and include troubleshooting-oriented API flow references
- Cross-link the runbook from docs index and related architecture, CLI, dashboard, getting-started, and settings docs
