Native HTML5 validation-hint capture (global invalid listener, mirror MARS-412)

Log ANY user-facing feedback incl native HTML5 constraint-validation hints (required/pattern/type=email/min-max) that bypass the JS toast/checkRequired path (browser renders natively, no JS fires). Capture via a capture-phase global 'invalid' listener (document.addEventListener('invalid',h,true)) → friction write path. ONE hook, no per-form edits, friction-tier only, no success logging, no PII. Reconciles the VENUS-176 D-batch 'cut': don't rewrite the 10 native-required forms into client components (correctly declined) — the global invalid hook captures them all at once. Reversible, independent of the MARS-411 column contract. Folding the build into the live toast-coverage audit.