Implement dual-limit tool output truncation to prevent context overflow:
- 4k tokens (~16k chars) for local models on local servers
- 10k tokens (~40k chars) for cloud models or remote servers
This helps preserve context window for local models with smaller
context windows while allowing larger outputs for cloud services.
- Add tests for OLLAMA_AGENT_DISABLE_WEBSEARCH/BASH env vars
- Add tests for ErrWebSearchAuthRequired error type
- Add tests for isLocalModel, isLocalServer, truncateToolOutputForLocalModel
- Add Ctrl+O toggle to expand/collapse tool output inline
- Show tools available in grey text at startup
- Add interactive signin flow when web search returns 401:
prompts user, shows signin URL, polls until auth completes
- Truncate tool output for local models to prevent context overflow
- Update help text with Ctrl+O keyboard shortcut
