fix(devx): pin metadata-lifecycle's two prose registry counts to the AST parse

The sentence under the overlay whitelist table states two registry-derived
quantities by hand -- "Those five are the complete allowOrgOverride: true set:
of the 27 types in DEFAULT_METADATA_TYPE_REGISTRY" -- and nothing checked
either. Registering a 28th type left the page asserting 27 with every gate
green, including the one that shipped alongside the sentence.

Adds LEG 3 (prose -> registry) to check-overlay-whitelist-table: it reads both
numbers out of the page and compares them with entries.length and the size of
the `true` filter, the two counts the gate already prints in --list. No count is
written into the script -- a literal 27 there would have moved the hand-kept
copy one file to the left.

The prose is untouched: parseCountToken reads digits AND English number-words
0..99, so "five" is pinned as written rather than digitised to suit the parser.
Above 99, or on any token the maps do not cover, the gate refuses rather than
guessing. An absent or reworded claim is RED, not a silent no-op.

Also derives the self-test's refusal-case count from the case arrays instead of
the hand-kept literal 21 -- the same defect class, in this gate's own summary.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015ahemw8RcTgqtxrj15PEZx

Author: claude