feat(doc-to-markdown): CJK bold spacing, JSON pretty-print, 31 tests, full rename cleanup

- Add CJK bold spacing fix: insert spaces around **bold** spans containing
  CJK characters for correct rendering (handles emoji adjacency, already-spaced)
- Add JSON pretty-print: auto-format JSON code blocks with 2-space indent
- Add 31 unit tests covering all post-processing functions
- Fix pandoc simple table detection (1-space column gaps)
- Fix image path double-nesting when --assets-dir ends with 'media'
- Rename all markdown-tools references across 15 files (README, QUICKSTART,
  marketplace.json, CLAUDE.md, meeting-minutes-taker, GitHub templates)
- Add 5-tool benchmark report (Docling/MarkItDown/Pandoc/Mammoth/ours)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/ISSUE_TEMPLATE/bug_report.md

@@ -16,7 +16,7 @@ Which skill is affected?
 
 - [ ] skill-creator
 - [ ] github-ops
-- [ ] markdown-tools
+- [ ] doc-to-markdown
 - [ ] mermaid-tools
 - [ ] statusline-generator
 - [ ] teams-channel-post-writer

.github/ISSUE_TEMPLATE/feature_request.md

@@ -20,7 +20,7 @@ Which skill would this enhance?
 
 - [ ] skill-creator
 - [ ] github-ops
-- [ ] markdown-tools
+- [ ] doc-to-markdown
 - [ ] mermaid-tools
 - [ ] statusline-generator
 - [ ] teams-channel-post-writer

.github/PULL_REQUEST_TEMPLATE.md

@@ -33,7 +33,7 @@ Which skills are affected by this PR?
 
 - [ ] skill-creator
 - [ ] github-ops
-- [ ] markdown-tools
+- [ ] doc-to-markdown
 - [ ] mermaid-tools
 - [ ] statusline-generator
 - [ ] teams-channel-post-writer