Spec/Subs: Implement Typographic Replacements & Character Entity Conversions

[webmaven]

Description

Implement typographic character replacements and character entity substitutions in compliance with the AsciiDoc specification outline.

Specification Reference

• Spec: link:https://gitlab.eclipse.org/eclipse/asciidoc-lang/asciidoc-lang/-/blob/main/spec/outline.adoc#user-content-typographic-replacements[Typographic Replacements]
• Examples:
  • Em dash (-- -> — or —)
  • En dash (- between digits -> –)
  • Ellipsis (... -> … or …)
  • Copyright ((C) -> ©), Registered ((R) -> ®), Trademark ((TM) -> ™)
  • Arrows (->, <-, =>, <=)
  • XML/HTML character references (Ӓ, &name;, )

Proposed Changes

• Tests (TDD):
  • Add unit tests in tests/test_inlines_parsing.py and tests/test_resolver.py.
  • Add local TCK fixtures for typographic replacement rules.
• Implementation:
  • Implement typographic substitutions in src/asciidoctrine/resolver.py or dedicated inline replacement pipeline.
  • Update docutils_backend.py and serializer.py to preserve or translate entity replacements.