Add comprehensive GitHub Copilot instructions and fix CI configuration for Red ORM development

[Copilot]

• [x] Create comprehensive GitHub Copilot instructions for Red ORM development
• [x] Add detailed development workflow documentation
• [x] Include critical timing information for long-running operations
• [x] Document database configuration for SQLite and PostgreSQL
• [x] Provide command reference and validation scenarios
• [x] Fix accidental deletion of API.md documentation - restored all API links
• [x] Configure Actions setup steps to resolve CI test failures
• [x] Fix PostgreSQL JSON path syntax errors and test isolation issues

PostgreSQL Test Fixes:

• Fixed JSONB path syntax in PostgreSQL driver - paths now use '\{path\}' format instead of '{ path }' to resolve "malformed array literal" errors
• Reduced PostgreSQL test parallelism from -j8 to -j2 to prevent table creation conflicts when tests run concurrently
• These changes address the main PostgreSQL test failures seen in CI

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💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.