Sækja opencode 1.14.21

Core
- Support pull diagnostics from LSP servers that use them, including C# and Kotlin.
- Fix project detection and caching for bare Git repos and worktrees. (@StevenTCramer)
- Improve session compaction so long threads keep more useful context when older history is summarized.
- Preserve UTF-8 BOMs when files are edited, patched, or rewritten through tools.
- Use Roslyn Language Server for C# support instead of csharp-ls. (@jmbryan4)
- Add the high reasoning variant for supported Mistral Small models. (@rubdos)
- Hide unsupported variants for Kimi models that do not expose them.
TUI
- Fail fast when opening an invalid or missing session instead of starting the TUI in a broken state.
- Skip upgrade checks when auto-update is disabled. (@rahuliyer95)
Desktop
- Keep project avatar previews consistent between the sidebar and edit dialog.
- Improve project icon overrides so uploaded icons and color fallbacks behave correctly in the edit dialog.
- Improve Linux desktop metadata for app listings and categorization. (@NN708)
Thank you to 6 community contributors:
- @rahuliyer95:
- fix(tui): don't check for version upgrades if it's disabled by the user (#20089)
- @github-actions[bot]:
- Update VOUCHED list
- @rubdos:
- feat: add Mistral Small reasoning variant support (issue #19479) (#23735)
- @jmbryan4:
- feat: replace csharp-ls with roslyn-language-server (#14463)
- @NN708:
- fix(desktop): update desktop file and MetaInfo file (#14933)
- @StevenTCramer:
- fix(project): use git common dir for bare repo project cache (#19054)