fix([issue-4282]): generalize repo-wide input accessible-name checks

[atomantic]

Closes #4282

Summary

• Generalize the client input accessible-name guard from Instances to all tracked JSX files.
• Recognize usable ARIA names, hidden inputs, explicit and implicit labels, native button-like names, and first-child FormField associations.
• Keep exact pre-existing source-anchor exceptions and track their remediation in Add accessible names to pre-existing unlabeled input controls #4297.

Tests

• cd client && npm test -- --run src/a11yConventions.test.js
• cd client && npm test -- --run
• cd client && npm run lint
• cd client && npm run build
• git diff --check
• Codex bounded audit: partial; 939 inputs scanned, 0 new offenders