v0.8.0 - robots_txt_validate detects managed / stale-edge robots

Managed-robots / Content-Signals detection - part 1 of the robots feature line. No new tools or prompts (57 tools / 13 prompts).

• robots_txt_validate now catches the Cloudflare Managed robots.txt / Content-Signals blind spot: a second cache-busted fetch detects a stale edge-cached robots.txt (and re-parses groups/sitemaps from the FRESH content), plus managed_robots_suspected, missing_sitemap, and content_signals parsing. All advisory; no new scope (FEEDBACK §27).

Install: uvx seo-monster or pip install seo-monster==0.8.0. Full notes in CHANGELOG.