The activity feed was returning decorated strings like "Vida (self-directed)"
and "@m3taversal" in the contributor field. The frontend uses that field as
both display label and routing handle, so /contributors/Vida%20(self-directed)
404s — Next fires notFound() in [handle]/page.tsx.
Root cause: _normalize_contributor only stripped @ and whitespace; it did not
lowercase or strip the " (self-directed)" suffix that extract.py and the
older backfill_submitted_by.py wrote into prs.submitted_by. Mixed-case
agent names (Vida vs vida) and pipeline decorators ("pipeline (reweave)")
both fell through.
Fix: lowercase + strip any trailing parenthetical decorator. Valid handles
match ^[a-z0-9][a-z0-9_-]{0,38}$ per attribution._HANDLE_RE and cannot
contain parens, so the strip is lossless.
DB simulation against 3612 merged-PR events: 0 orphan handles after
normalization (was 12 orphan label-variants before).
No KB writes — pure read-side normalization in the API layer.
