refactor: modularize vinca recipe and pipeline generation

[wolfv]

Summary

This is a broad, behavior-preserving cleanup of vinca focused on making the codebase easier to understand and maintain.

• reduce main.py from ~1,400 lines to ~700 lines
• split configuration loading, platform detection, mutex recipes, recipe output generation, and source generation into focused modules
• extract shared GitHub Actions pipeline helpers into pipeline.py
• break the 347-line generate_output implementation into named, testable helpers
• avoid mutating package metadata and pipeline stage inputs
• fix transitive CI dependency traversal (including cycle handling)
• remove the obsolete Azure pipeline generator and vinca-azure entry point
• rename and modernize the packaged CI scripts used by the GitHub Actions generator
• add import sorting and bugbear checks to Ruff
• improve exception chaining for archive/package metadata failures
• preserve compatibility entry points in vinca.main

Verification

• 137 tests pass (up from 113 on master)
• ruff check . passes
• ruff format --check . passes
• git diff --check passes
• all refactored modules import successfully
• vinca --help smoke test passes
• representative normal and dummy recipe outputs were compared byte-for-byte as JSON against the implementation on master

[traversaro]

This is quite nice, but I think it would be nice to test this in an actual robostack/ros-* repos.