Extend OCR-helpers ledger row for PR #384's marker-detection change

[WilfordGrimley]

Description

Conventions-compliance pass over today's (2026-07-23) shipped work
against docs/upstreaming/extractable-primitives.md's own criteria.

local_ocr.py's parse_legal_line (_PROXY_MARKER_RE, copyright-year
regex) is a pure text-in/struct-out classifier with zero fork-only
imports, widened today by PR #384 to catch maker-brand-glued proxy
markers ("JestaProxy"). It wasn't listed in the existing "OCR
crop/preprocessing helpers" row's function set even though it qualifies
by the same standard as every other function already in that row —
added it, plus a Detail-notes sentence explaining why it's included
(mirroring how validate_against_candidates/find_matching_candidates
are explained as excluded there).

Everything else audited this pass (pilot_run_lifecycle.py,
local_layout_class_cast.py, retract_stage_d_by_run_id.py, the #380
reparse/lexicon changes) is verified accurate or genuinely
non-qualifying — no further ledger edits. modern_artist_credit.py
(#390) is judged but not rowed since it's unmerged (file doesn't exist
on master yet — the ledger's own "read directly from the repo on
master" ground truth). scripts/ops/crash_drill.sh and a
"sequence-independence test pattern" PR referenced in this pass's brief
don't exist as any PR (open/closed/merged) or committed file anywhere
in the repo as of this audit — nothing to check in against. PR #352's
button-divergence documentation requirement (owner's "if we diverge
from upstream, document it" rule) is already satisfied — verified
present at docs/upstreaming/readiness-audit.md §10 with matching
// diverges from upstream: comments at each cited call site.

Docs-only, no code changes.

Checklist

• I have installed pre-commit and installed the hooks with pre-commit install before creating any commits.
• N/A — docs-only change, no tests apply.
• I have manually tested my changes as follows: ran python3 .github/scripts/docs_lint.py --strict (clean) and the link-rewrite-parity/readme-parity fixture test scripts (all passing, unaffected by this change).
• I have updated any relevant documentation or created new documentation where appropriate. (This PR IS the documentation update.)