v2.0.6 — event-loop fix (content_audit + extended_checks)

Hotfix: content_audit and extended_checks modules silently failed during the audit finalize chain on multi-page crawls with "event-loop error", leaving the audit zip without content-audit.csv and extended-checks.csv. Root cause was racy reuse of asyncio.new_event_loop() across sequential module calls in Python 3.12. Replaced with idiomatic asyncio.run() in all 3 affected modules (content_audit.py, extended_checks.py, external_links.py).

Verified on a real 90-page adityaarsharma.com audit: 185 extended_checks findings + 50 pages content-audited, both CSVs in the zip with real content.

No API change. No version bump needed in server.json/Glama listings (still 2.0.5 there until v2.1 ships).