v0.58.0: Local settings override, environment variable references in custom models, and Missions UX improvements

New features

- Local settings override - New settings.local.json for local project/folder-level settings overrides
- Environment variable references - Custom model API keys now support environment variable references
- Gemini 3.1 Pro model - Added Gemini 3.1 Pro model support
- Missions planning pausing - Allow pausing during planning phases with in-context resume in Mission Control view

Bug fixes

- Anthropic provider reset - Fixed stale Anthropic provider state on model switch
- MCP toggle effects - MCP toggle changes now apply immediately without restart
- Browser MCP isolation - Stopped auto-adding --isolated flag for browser MCP servers
- Windows PowerShell - Fixed PowerShell execution issues on Windows
- GLM 4.7 routing - Fixed GLM 4.7 model routing issues
- Ctrl+G spam prevention - Blocked Ctrl+G while the agent is streaming to prevent notification spam