Close the migrated vocabulary schema

[dcellison]

Summary

• require description, articulatory_notes, and structured examples directly in every lexicon entry
• remove the retired concept and grammatical_notes properties and their migration-era fallback branches
• replace legacy-shape acceptance tests with direct tests for missing-field and retired-field rejection
• stop scanning retired fields as active lexicon prose while preserving the completed coverage ledger as regression evidence
• update the vocabulary, validator, voice, handoff, protocol, decision, and near-term planning references to describe the closed contract

No vocabulary entry, Phi word, gloss, example, or generated lexicon reference changes in this PR.

Behaviour

The schema now rejects an entry when articulatory_notes or examples is absent, even if sound_symbolism or old grammar prose is present. Because additionalProperties remains false, either retired property is also rejected explicitly. The coverage report still classifies legacy, partial, dual, and target shapes, but the first three are evidence of a regression rather than accepted schema states.

NTP-01 is marked done under D115, and NTP-02 becomes the next package in the status-tracked plan.

Prose review

The changed reader-facing reference prose received the required Humanizer and Phi voice pass. One dense validator-coverage sentence had become a long mechanical chain; it is now a short inventory whose items can be scanned independently.

Checks

• python3 scripts/validate_examples.py (1,305 entries, 0 errors, 0 warnings)
• python3 scripts/validate_sentences.py (3,313 examples, 0 errors)
• python3 scripts/test_sentence_validator.py (25 tests)
• python3 scripts/test_vocabulary_schema.py (25 tests)
• python3 scripts/content_vocabulary_decisions.py --check (82 batches, 280 decisions)
• python3 scripts/test_content_vocabulary_decisions.py (8 tests)
• python3 scripts/test_name_forms.py (20 tests)
• python3 scripts/test_translation_layers.py (11 tests)
• python3 scripts/translation_process_status.py --check (20 translations)
• python3 scripts/test_translation_process_status.py (9 tests)
• python3 scripts/audit_phonetic_neighbors.py --output /tmp/phonetic_neighbors_ntp01.txt and baseline comparison (250 pairs, unchanged)
• python3 scripts/vocabulary_prose_coverage.py (1,305 target entries, committed report unchanged)
• python3 scripts/generate_reference.py (generated references unchanged)
• python3 scripts/build_site.py
• git diff --check