feat(tool/looker): add conversation CRUD tools

[hiracky16]

1. Description

This PR implements the Phase 1 of Looker's Conversational Analytics API integration by adding five tools for Conversation CRUD management. These tools follow the established patterns and the strict security/annotation guidelines established in PR #2830.

New Tools Added:

• looker-create-conversation: Starts a new session with an AI agent.
• looker-list-conversations: Searches and lists existing conversation sessions.
• looker-get-conversation: Retrieves detailed metadata for a specific session.
• looker-update-conversation: Modifies conversation attributes (e.g., name).
• looker-delete-conversation: Deletes a conversation session (marked with DestructiveHint).

Key Highlights:

• Annotation Protection: Strictly adheres to PR feat(tools/looker): Looker agent management from MCP #2830 patterns by forcing ReadOnlyHint and DestructiveHint in the Initialize method to ensure safe LLM interaction.
• Documentation: Added CI-compliant markdown files in docs/en/integrations/looker/tools/ with correct H2 ordering and required shortcodes.
• Testing: Unit tests verify correct configuration parsing for all new tools.

2. PR Checklist

• Make sure to open an issue as a bug/issue before writing your code!
• Ensure the tests and linter pass
• Code coverage does not decrease
• Appropriate docs were updated
• Make sure to add ! if this involves a breaking change (N/A, additive only)

3. Issue Reference

Related to the work on Looker Conversational Analytics integration. 🦕

[gemini-code-assist]

Code Review

This pull request introduces five new Looker tools for managing conversation sessions: looker-create-conversation, looker-delete-conversation, looker-get-conversation, looker-list-conversations, and looker-update-conversation. The implementation includes the necessary Go logic, unit tests, and documentation for each tool. Several issues were identified regarding logging practices, specifically the use of ErrorContext for informational messages and the lack of structured key-value pairs. Additionally, the documentation titles need to be updated to follow the repository's naming convention, and mutating tools like 'create' and 'update' should include the DestructiveHint annotation for consistency. Finally, the imports in cmd/internal/imports.go should be reordered alphabetically.