Sync changes

Improvements

• CoreAllow specifying custom models file path via OPENCODE_MODELS_PATH environment variable
• CoreEnsure models configuration is not empty before loading
• CoreMake skills invokable as slash commands in the TUI
• CoreDon't follow symbolic links by default in grep and ripgrep operations
• CorePrevent parallel test runs from contaminating environment variables
• CoreEnsure Mistral ordering fixes also apply to Devstral
• CoreAdd Copilot-specific provider to properly handle reasoning tokens@SteffenDE
• CoreRespect OPENCODE_MODELS_URL environment variable in build process@bbartels
• CoreUse snake_case for thinking parameter with OpenAI-compatible APIs@Chesars
• CoreBump AI SDK packages
• CoreEnsure ask question tool isn't included when using acp
• CoreHandle redirected statement treesitter node in bash permissions@pschiel
• CoreRemove special case handling for Google Vertex Anthropic provider in response generation@MichaelYochpaz
• CoreExclude chat models from textVerbosity setting
• DesktopRevert transitions, spacing, scroll fade, and prompt area updates
• DesktopAdd session actions tests@neriousy
• DesktopRefactored tests and added project tests@neriousy