feat: optimize skills + add pipeline handoff chaining across 9 skills

asr-transcribe-to-text:
- Add local MLX transcription path (macOS Apple Silicon, 15-27x realtime)
- Add bundled script transcribe_local_mlx.py with max_tokens=200000
- Add local_mlx_guide.md with benchmarks and truncation trap docs
- Auto-detect platform and recommend local vs remote mode
- Fix audio extraction format (MP3 → WAV 16kHz mono PCM)
- Add Step 5: recommend transcript-fixer after transcription

transcript-fixer:
- Optimize SKILL.md from 289 → 153 lines (best practices compliance)
- Move FALSE_POSITIVE_RISKS (40 lines) to references/false_positive_guide.md
- Move Example Session to references/example_session.md
- Improve description for better triggering (226 → 580 chars)
- Add handoff to meeting-minutes-taker

skill-creator:
- Add "Pipeline Handoff" pattern to Skill Writing Guide
- Add pipeline check reminder in Step 4 (Edit the Skill)

Pipeline handoffs added to 8 skills forming 6 chains:
- youtube-downloader → asr-transcribe-to-text → transcript-fixer → meeting-minutes-taker → pdf/ppt-creator
- deep-research → fact-checker → pdf/ppt-creator
- doc-to-markdown → docs-cleaner / fact-checker
- claude-code-history-files-finder → continue-claude-work

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

deep-research/SKILL.md

@@ -528,3 +528,17 @@ Report: `[P7 complete] {N} spot-checks, {M} violations fixed.`
 - **Skipping counter-review** — mandatory P6 must find ≥3 issues
 - **CIRCULAR VERIFICATION** — never use user's private data to "discover" what they already know about themselves
 - **IGNORING EXCLUSIVE SOURCES** — when user provides Crunchbase Pro etc. for competitor research, USE IT
+
+## Next Step: Verify and Deliver
+
+After completing research, suggest verification and output:
+
+```
+Research report complete: [N] sources cited, [M] claims made.
+
+Options:
+A) Verify facts — run /fact-checker on the report (Recommended)
+B) Create slides — run /ppt-creator from the findings
+C) Export as PDF — run /pdf-creator for formal delivery
+D) No thanks — the report is ready as-is
+```