Skill: frontend/form-validation

Purpose

Implement consistent form validation and error UX:

• validation rules (required, format, ranges)
• error messaging and accessibility
• submit gating (disabled states, preventing double submit)
• server error handling and mapping where applicable

Inputs

• Form location (route/component)
• Fields and constraints (required/optional, format, min/max)
• Submit behavior (create/update, optimistic allowed yes/no)
• Error handling expectations (inline vs toast vs summary)
• Repo profile (preferred): <repo>/REPO_PROFILE.json (form library, patterns)