feat(rules): compare typed source properties #16

Summary

• Add typed equality and ordering checks against another selected property on the same source.
• Capture comparison values with the failure decision so messages agree with the tested value.
• Supply named comparison path and value arguments, with caller overrides taking precedence.
• Update source mirrors, package examples, and boundary tests.

Closes #15.

Validation

• rg --files src test -g '*.pudu' | xargs pudu check
• pudu lint src test
• pudu fmt --check src test
• pudu test test — 17 suites, 150 assertions
• pudu build src/Main.pudu -o /tmp/pudu-lang-validator
• Compiled CLI --version smoke run
• Independent source and wiki review