v0.4.5 — Slack Token Fix & Copilot Bundling

Hotfix release that resolves Slack sources being unusable due to the token refresh system incorrectly handling non-refreshable OAuth tokens, plus Copilot CLI bundling improvements.

Bug Fixes

• Fixed non-refreshable OAuth tokens (Slack) being broken by ensureFreshToken() — tokens without a refreshToken (e.g. Slack bot tokens) now return as-is instead of falling through to a refresh that fails and marks the source needs_auth (e358e414)
• Fixed refresh cooldown not clearing on re-authentication — after re-authenticating a source, the 5-minute cooldown is now immediately cleared so the source is usable without waiting (e358e414)
• Fixed Copilot CLI on Windows — added copilot.exe to extraResources to avoid EBUSY file locking during electron-builder packaging (d4cda5f2)
• Added copilot to the LLM provider type validator schema (d4cda5f2)

Build & CI

• Added Copilot CLI bundle verification to CI workflows for all platforms (macOS arm64/x64, Linux, Windows) (d4cda5f2)
• Copilot CLI native binary now properly vendored per-platform in build scripts with size verification (d4cda5f2)

Documentation

• Added Troubleshooting section with debug mode commands to README (53394694)