feat: add AlgorithmicEvaluator, migrate to log crate, fix flush value calculation

- Add AlgorithmicEvaluator wrapper for direct hand evaluation without
  lookup tables, with proper Result-based error handling
- Replace all println! and #[cfg(debug_assertions)] debug output with
  log crate macros (log::info!, log::debug!, log::warn!)
- Fix calculate_flush_value to use base-13 encoding for unique flush
  hand values instead of simple linear sum
- Fix is_straight to use cleaner control flow for regular and wheel
  straight detection
- Remove jump table HighCard/value=0 guard in evaluate_5_card to
  simplify evaluation path
- Add evaluate_n_card_hand_public as pub(crate) for AlgorithmicEvaluator
- Add .gitignore to exclude target/ and .idea/ from version control
- Add comprehensive tests for AlgorithmicEvaluator (14 test cases)
- Update README with new API usage examples
- Add log dependency to Cargo.toml
- Add placeholder modules for future implementations (tables_new,
  benchmark_utils, integration_utils, test_utils)

.gitignore

@@ -0,0 +1,10 @@
+# Build artifacts
+/target
+
+# IDE
+.idea/
+*.iml
+
+# OS
+.DS_Store
+Thumbs.db