Added AI assist with pre-defined instructions

[ric-v]

This pull request delivers a significant update to the PostgreSQL Explorer extension, focusing on enhanced AI integration, expanded command palette, improved language support, and configuration flexibility. The update introduces new AI-powered features for SQL assistance, adds support for multiple AI providers, and improves the user interface with more commands and refined context menus. It also updates documentation and ensures compatibility with newer versions of VS Code.

AI Integration and User Experience Improvements:

• Introduced "Ask AI" CodeLens and inline toolbar button in notebook cells, enabling users to access AI-powered SQL help directly above queries. Added quick actions for explaining, fixing, optimizing, and formatting SQL, with support for Google Gemini, OpenAI, Anthropic, and GitHub Copilot. [1] [2] [3] [4] [5] [6]
• Added new configuration settings for selecting AI provider, API key, model, and custom endpoint, allowing flexible integration with different AI services.

Command Palette and Context Menu Expansion:

• Added new commands for creating schemas, roles, databases, and enabling extensions, as well as database scripting (ALTER, DROP, CREATE) and AI assistance commands. Improved context menu logic for more granular control over where commands appear in the UI. [1] [2] [3] [4] [5] [6] [7]

Language and Compatibility Updates:

• Registered the postgres language with correct aliases and file extensions, fixing CodeLens visibility issues and ensuring proper syntax highlighting and AI integration. [1] [2]
• Updated VS Code engine requirement to ^1.90.0 and bumped extension version to 0.3.0 for compatibility and semantic versioning adherence. [1] [2] [3]

Documentation Enhancements:

• Added a comprehensive CHANGELOG.md following Keep a Changelog and Semantic Versioning standards, documenting all notable changes, fixes, and new features. Improved README.md with clear highlights of new AI features and usage guides. [1] [2] [3]

Build and Activation Fixes:

• Fixed the extension entry point in package.json to ./dist/extension.js for correct loading from the VS Code marketplace. Updated activation events to ensure all commands and views are registered properly.

These changes collectively provide a more powerful, flexible, and user-friendly experience for PostgreSQL Explorer users, especially those leveraging AI for SQL development.