Pin dependencies; drop dead severity/quality-score code from review.py

requirements.txt (new) pins python-telegram-bot, feedparser, aiohttp,
and beautifulsoup4 to their current stable versions — the repo had no
lockfile or pinned deps at all, just a pip-install line in the README.

validation/review.py still had a --severity filter and printed a
quality_score that content_classifier.py stopped producing a while
back (see "Remove severity and quality scoring, classifier is
extraction-only"). Every record scored UNKNOWN/?, so the flag could
never match anything. Removed; --category/--has/--today/--limit and
the extracted-field printing are unchanged.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

requirements.txt

@@ -0,0 +1,5 @@
+# Hand-curated dependency pins; this project does not have a lockfile.
+python-telegram-bot==22.8
+feedparser==6.0.14
+aiohttp==3.14.3
+beautifulsoup4==4.15.0