v0.7.9 — Reliable WebSocket Delivery, Copilot Model Overhaul & Windows Fixes

Features

Reliable WebSocket event delivery — WebSocket connections now use sequence-number tracking with automatic replay on reconnect. Events are buffered server-side and replayed when a client reconnects, eliminating dropped events during network interruptions. Includes stale reconnect recovery, watch resubscription, and guards against double onClientDisconnected calls.

Copilot model management overhaul — Complete rewrite of GitHub Copilot model discovery and sync. Replaced CopilotClient CLI with direct HTTP API calls, added a 3-tier fallback chain (HTTP API → CLI → static catalog), and fixed multiple race conditions around model refresh. Models without an explicit enabled policy are now excluded, legacy GPT-4/3.5 models are filtered out, and stale data no longer overwrites good model lists. Partially addresses #418.
1M context activation — Fixed Opus 4.6 and Sonnet 4.6 1M context window by switching from beta headers to the [1m] model suffix.
Windows: VC++ runtime check — Hardened vcredist detection with better type safety, test coverage, and error handling.
Windows: binary document tools — Document conversion (markitdown, pdf-tool, etc.) and skill asset access now work correctly on Windows.

Windows VC++ toast — Replaced the blocking startup dialog for missing VC++ redistributables with a non-blocking in-app toast notification.
Copilot model refresh logging — Added diagnostic logging to aid troubleshooting of model sync issues.