[andrewzolotukhin]

Original request

Support blur validation and rejected inline edits in the headless form package, with no imposed UI or changes to existing defaults.

What changed

• Add opt-in validateOnBlur: immediately validate current values, cancel pending debounce, and touch only the blurred field.
• Add awaitable FormSubmitOptions.onInvalid(result) inside the managed submission lock.
• Add opt-in refreshValidationRules for changed bounds/messages with a fixed field model. Preserve raw values, baselines, dirty/touched state and suppress stale validation/submission callbacks.
• Suppress stale invalid callbacks after edits, reset or unmount; callback exceptions propagate without being translated as failed writes.
• Add lifecycle regressions, public type assertions, JSDoc, README examples and a minor changeset.

Reasoning

Applications can retain their existing controls and decide whether rejected inline edits restore a saved baseline. The package owns validation timing, duplicate protection and stale-result handling. Both additions are optional, preserving existing behavior.

Blog post

Skipped: internal headless lifecycle integration. Public contracts are documented in the package README and JSDoc.

Screenshots / preview evidence

No visual surface or configured preview is changed by this library PR. DOM/hook tests verify behavior without a UI dependency; consumer visual acceptance is separate.

Validation

• npm run lint: pass.
• npm run build: all 24 package builds pass.
• npm run test: 5,396 tests across 303 files pass; no type errors.
• The full rerun includes blur, invalid-submit and rule-refresh DOM/hook regressions and public API type assertions.
• Current candidate includes the rule-refresh follow-up; CI must pass on the latest head before merge/publication.
• No application telemetry is applicable to this library-only PR.