feat(compare): add effect-aware diffs and printer routing

[PakitoSec]

Summary

• add effect support to ExpectedResult and diffing so comparisons can detect conclusion-vs-additive changes even when verdicts match
• expand diff rendering with nested observable/signal context, effect annotations, score band coloring, exported SignalDiff, and summary graphs shown by default
• route CLI and Cyvest.display_* rendering through caller-supplied printers to keep rich output on one stream, and update docs/examples to explain the new behavior

Testing

• update comparison, rendering, and CLI tests to cover effect-aware rules, nested diff trees, printer routing, default graph output, and explanation rendering