Recover HTML numeric character references

[rogerchappel]

Summary

• apply HTML numeric-reference recovery for null, surrogate, out-of-range, and C1 replacement-table values
• accept valid semicolonless decimal and hexadecimal references without consuming following non-numeric text
• add fixture-backed library/conversion regressions and document the public behavior

Commits

• 7ca8da0 test: cover HTML numeric reference recovery
• d61c479 fix: recover HTML numeric character references
• c99e444 docs: describe numeric entity recovery

Verification

• npm ci
• npm run release:check (33 tests plus syntax, build, smoke, package smoke, release contract)
• bash scripts/validate.sh
• git diff --check origin/main...HEAD
• all authors and committers verified as Roger Chappel miscanalysis@gmail.com

[rogerchappel]

Automated merge note

Triage class: auto-merge
Summary: routine HTML numeric-character-reference recovery across parser, fixtures, tests, and README (4 files, +47/-11).
Checks run: CI test completed SUCCESS; final diff, mergeability, branch protection, and head SHA verified.
Rebased/CI-repaired: no.
Verified head SHA: c99e444.