v0.7.5 — anonymous usage telemetry (opt-out) + crawl fixes

Highlights

• Anonymous usage telemetry (opt-out, transparent) — counts real users (DAU/MAU) instead of raw download numbers. One tiny ping per 24 h: hashed machine id + version + Python version + OS family. No IP stored, no URLs, no content. Opt out with PYRECRAWL_NO_TELEMETRY=1 or DO_NOT_TRACK=1. Collector is a self-hostable Cloudflare Worker + D1 (workers/telemetry/) — no third-party analytics.
• crawl: css_selector + max_depth now honored in every tier (were silently dropped)
• crawl/map: link harvest only yields real pages (junk links filtered)
• search_papers: arXiv API over HTTPS + unknown-source guard
• CLI: Codex TOML regex fix (stops at next section header)
• Docs: honest scrape docstring + 13-tool selfcheck

Full diff: v0.7.3...v0.7.5