fix(communication): validate declared Git authors

[tom-sapletta-com]

Ticket: ticket-032

Restores the participant-registry mismatch warning lost during helper extraction. Declared Git authors are retained only for validation; emitted identity metadata remains owned by the trusted participant registry.

Validation on base caf6551:

• npm run build: passed
• focused communication identity tests: 2 passed, 0 failed
• full fresh suite: 327 passed, 10 failed, 1 skipped out of 338
• targeted git-authors regression removed
• remaining failures belong to independent tickets 030/031 and the prompt-path repair
• diff check and allowed-path scope: passed
• governance: only four inherited ticket-018/ticket-019 findings

No test assertion or identity trust boundary changed. Independent trusted review remains required.

[tom-sapletta-com]

Combined regression integration evidence (not merge approval): base caf6551 plus implementation commits 9c25942, bbd236f, c5db5fb, and f96c0a8 was built in a detached uncommitted worktree. npm run build passed; full npm test reported 338 tests, 337 passed, 0 failed, and 1 environment-dependent JDK skip. The combined implementation diff is 4 files, 9 insertions, 6 deletions. Required governance checks and independent review remain authoritative.

[tom-sapletta-com]

Zamykam jako superseded przez zwalidowaną linię publish/validated-repair-031; walidacja deklarowanych autorów Git jest już obecna w jej drzewie.