Introduce a commercial license option alongside AGPL-3.0-only, require a
CLA for contributors, and document the terms in COMMERCIAL.md and
NOTICE. Add a script to stamp SPDX headers on Go files and apply it
across the tree.
Introduce web.FieldErrors for server-side per-field messages. Update
templates to render is-invalid/invalid-feedback and add a fieldErr
template helper that scopes errors to a specific form instance. Update
operator handlers to validate inputs, populate FieldErrors, and render
form-specific error state; add a no-op fieldErr stub to fedwiki partials
so parsing succeeds.
cgalo5758