Release v2.3.0: bounded extraction fixes and contract alignment

[NickLeko]

This releases exp-001's five deterministic fixes: auxiliary-verb diagnosis negation, reflex descriptor linkage, intact-reflex recognition, negated numeric-strength review, and cross-sentence sleep-study date association. Owner-approved setup rewrites retain correction, attestation and wrong-READY archive coverage; independent case 17 now correctly labels its missing study date.

Release preparation adds no further product logic. Engine/app version is 2.3.0; record schema remains 2.0.0. Contract JSON now solely drives strict markers, with two explicit open-gap examples replacing obsolete resolved-failure annotations.

Validation:

• make test: 1123 passed, 10 xfailed. make lint passes.
• Corpus 52/52, zero false PENDING_VERIFICATION; original authored cases 45/45. Expanded 47 retain two disclosed false pending setup counterexamples.
• Fixed acceptance-clock generation: 25 files audited, 12 changed only engine_version/app_version from 2.2.0 to 2.3.0. Governance outputs are byte-for-byte unchanged; no extraction-related generated field differs.
• All 33 Markdown documents scanned for stale counts and failure/version claims. Historical release and experiment measurements remain unchanged.

See release notes, generation audit, documentation audit and experiment report.

The required 41-case external held-out result is included verbatim and attributed to the owner; its inputs were not accessed during development. Review only: do not merge or tag as part of this preparation.