feat(ai_chat): add Tavily search plugin

[g1331]

This PR adds a new AI Chat plugin: Tavily – a search engine purpose-built for AI.

Summary:

• New plugin: tavily_search implemented in modules/self_contained/ai_chat/plugins/tavily_search.py
• Config model TavilySearchConfig with fields: api_key (required), search_depth (basic/advanced), max_results, include_answer, include_raw_content
• Lazy import of tavily-python to avoid hard dependency unless the plugin is enabled
• Registered the plugin in plugins_registry.py
• No default enablement; users must provide api_key in data/ai_chat/ai_chat.json

Notes:

• Dependency not added automatically; recommend installing via uv add tavily-python
• Syntax check via python -m compileall passed.

Please review. Once merged, I can follow up with docs and tests if desired.

---

Pull Request opened by Augment Code with guidance from the PR author

[Copilot]

Pull Request Overview

This PR adds a new Tavily search plugin to the AI Chat module, providing AI-powered web search capabilities. Tavily is a search engine specifically designed for AI applications.

Key changes:

• Implements a new TavilySearchPlugin with comprehensive configuration options including search depth, result limits, and content inclusion settings
• Adds lazy loading of the tavily-python dependency to avoid hard requirements
• Registers the plugin in the central plugins registry for availability in the AI chat system

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
modules/self_contained/ai_chat/plugins/tavily_search.py	New plugin implementation with config model, search functionality, and error handling
modules/self_contained/ai_chat/plugins_registry.py	Registers the new Tavily search plugin in the system

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Copilot]

Using bare Exception is too broad. Consider catching specific exceptions like ValueError or TypeError for the int() conversion to provide more precise error handling.

Suggested change

	except Exception:
	except (ValueError, TypeError):

[Copilot]

Using bare Exception is too broad. Consider catching ImportError or ModuleNotFoundError specifically since this is handling import failures.

Suggested change

	except Exception:
	except (ImportError, ModuleNotFoundError):

[Copilot]

Using bare Exception is too broad. Consider catching specific exceptions that the Tavily client might raise, such as authentication errors, network timeouts, or API-specific exceptions to provide more targeted error messages.