Kotlin support

[Kevinrob]

Summary

This PR adds support for the Kotlin programming language and Kotlin Script (.kts) to the codetree MCP server. It enables structured code understanding, call graph analysis, and complexity metrics for Kotlin projects, which is particularly useful for Android and Gradle-based environments.

Changes

• Dependency: Added tree-sitter-kotlin to pyproject.toml.
• Plugin Implementation: Created KotlinPlugin in src/codetree/languages/kotlin.py with support for:
  • Skeleton extraction (Classes, Objects, Interfaces, and Functions).
  • Symbol source retrieval.
  • Call graph analysis (detecting function/method invocations).
  • Cyclomatic complexity calculation.
  • Local variable and parameter extraction.
• Registry: Registered .kt and .kts extensions to use the new KotlinPlugin.
• Documentation: Updated README.md, AGENTS.md, and docs/LANDING_PAGE.md to include Kotlin in the list of supported languages.
• Project Maintenance: Added uv.lock to .gitignore

Test plan

• Ran pytest — all tests pass (including 33 new Kotlin-specific tests)
• Added new tests for changed behavior (Basic and Comprehensive test suites for Kotlin)
• Tested with a real MCP client (Successfully indexed a large Android project with ~19MB graph database)

Related issues