fix(matrix): make bang-command resolution robust + fix dead skill-command branch

Follow-up to the salvaged contributor commit:

- Underscore→hyphen tolerance now emits a resolvable token. Previously
  the detect set accepted the hyphenated variant but emit returned the
  raw token, so '!set_home' produced '/set_home' which the dispatcher
  could not resolve. Now emits '/set-home'. Aliases are left as-is — the
  gateway dispatcher canonicalizes them itself.
- Fix dead skill-command branch: skill command keys are stored
  slash-prefixed (e.g. '/arxiv') in get_skill_commands(), but the check
  compared the bare token, so '!arxiv' never normalized. Now compares
  the '/candidate' form, making skill aliases (e.g. !gif-search) work.
- Re-run bang normalization after Matrix reply-fallback stripping so a
  quoted reply whose content is a bang command reaches command parity
  with the slash form.
- Replace silent 'except Exception: pass' with logger.debug(exc_info=True).
- Add AUTHOR_MAP entry for @nepenth.

Tests: +5 (underscore-alias, skill-command branch, quoted-reply bang +
slash parity). 162 Matrix tests pass.

scripts/release.py

@@ -46,6 +46,7 @@ ACP_REGISTRY_MANIFEST = REPO_ROOT / "acp_registry" / "agent.json"
 # Auto-extracted from noreply emails + manual overrides
 AUTHOR_MAP = {
     "liliangjya@gmail.com": "truenorth-lj",
+    "16943149+nepenth@users.noreply.github.com": "nepenth",
     "ben.bartholomew@vectorize.io": "benfrank241",
     "74339271+SaguaroDev@users.noreply.github.com": "SaguaroDev",
     "subw3@mail2.sysu.edu.cn": "Subway2023",