feat(reference-curator): add --save-raw, --no-distill flags + OurSEO crawler integration

- Add --save-raw flag: saves intact crawled markdown in raw/ subdirectory
  alongside distilled content, with YAML frontmatter for traceability
- Add --no-distill flag: skip stages 4-5 (distiller + QA reviewer),
  pure archival mode for raw documentation capture
- Integrate OurSEO BaseAsyncClient + PageAnalyzer as seo-aiohttp backend:
  token-bucket rate limiting, semaphore concurrency, tenacity retries,
  full page metadata extraction (headings, links, schema, OG)
- New seo_crawler_adapter.py: crawl URLs, sitemaps, link discovery, manifests
  with progress tracking and resume support
- Update crawler selection: docs sites now default to seo-aiohttp
- Update crawl_config.yaml with seo-aiohttp routing rules
- Update pipeline orchestrator with flag resolution and skip paths
- Update README.md and USER-GUIDE.md with raw mode documentation

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

custom-skills/90-reference-curator/05-quality-reviewer/code/CLAUDE.md

@@ -5,6 +5,12 @@ Pre-distillation quality gate using Gemini CLI as an independent evaluator. Asse
 ## Trigger Keywords
 "review content", "quality check", "QA review", "evaluate sources", "check reference quality"
 
+## Skip Condition
+
+**This entire stage is skipped when `--no-distill` is active.**
+
+When the pipeline uses `--no-distill`, quality review is bypassed because there is no distilled content to evaluate. Raw crawled content goes directly to the exporter.
+
 ## Primary Flow: Gemini Pre-Distillation Gate
 
 ```