Enhance documentation: Move docs to class docstrings and improve README files

[perrozzi]

This PR tries to improves the documentation structure and quality across the UTCP codebase by adding some more documentation into class docstrings and enhancing all README files with comprehensive cross-references.

Changes Made

Documentation Migration

• Added protocol documentation into class docstrings for better maintainability and discoverability
• Enhanced class documentation for HTTP, CLI, MCP, and Text plugins with usage examples and configuration patterns
• Added documentation for previously undocumented classes including post-processors, search strategies, and utility components

README Improvements

• Main README: Added repository structure section and improved protocol plugin table with cross-references
• Core README: Rewrite with API reference, extension points, and development instructions
• Plugin READMEs: Created comprehensive documentation for all plugins:
  • HTTP Plugin: Configuration examples, OpenAPI integration, authentication patterns
  • CLI Plugin: Command execution, security considerations, error handling
  • MCP Plugin: Migration scenarios, debugging examples, performance considerations
  • Text Plugin: Clarified support for both local files AND remote OpenAPI specs with examples

Cross-References

• Added proper cross-references between all README files
• Created navigation links between core and plugin documentation
• Linked to external resources (examples repository, specifications)

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Summary by cubic

Migrated protocol and plugin docs into class docstrings and overhauled all README files for clearer setup, usage, and cross-references. Improves in-code discoverability and adds copy-paste examples for HTTP, CLI, MCP, and Text plugins.

• New Features
  • Added comprehensive docstrings for core components (exceptions, tag/description search, plugin loader) and post-processors with usage and config notes.
  • Documented plugin call templates (HTTP, CLI, MCP) directly in code with practical configuration examples and security tips.
  • Reworked main README with repository structure, quick start, and a plugin matrix.
  • Rewrote core README with architecture, quick start, config, extension points, testing, and build steps.
  • Expanded plugin READMEs (HTTP, CLI, MCP, Text) with features, install steps, rich config examples, OpenAPI integration, migration guidance (MCP), security/error handling, and testing snippets.
  • Added consistent cross-links between core and plugin docs and to the examples repository.
  • Docs-only changes; no runtime behavior impact.

[cubic-dev-ai]

15 issues found across 15 files

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