chore: remove dead legacy form-data migration commands

MigrateLegacyFormsData and VerifyFormsDataIntegrity exist to migrate the
pre-form-builder registration_form_fields / registration_field_templates
/ person_field_values tables into the current form_* tables. Those
legacy tables have been dropped from the dev database (verified via the
2026_04_20 drop_remaining_legacy_registration_tables migration), which
means the migrator's top-of-handle() guard always short-circuits the
run. The verify command is only reachable via
MigrateLegacyFormsData::verify() — also dead with its caller gone.

CLAUDE.md delete > adapt. These commands would also break the WS-5d
commit 5 column drop: MigrateLegacyFormsData:225 writes \$rff->options
straight to form_fields.options, which will not exist after commit 5.
Cleaning up before WS-5d starts keeps the dev tree consistent throughout
the refactor.

The two stale comment references in FormBuilderDevSeeder (header docblock
and seedSubmissionsForEvent docblock) plus the migration docblock that
mentions the migrator self-skip behaviour are scrubbed in the same
commit so no orphan references remain.

No production data exists; no migration safety net is being removed.

Tests: 1158 → 1158 green (no test coverage existed for these commands;
they were truly orphaned).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

api/database/seeders/FormBuilderDevSeeder.php

@@ -29,7 +29,7 @@ use Illuminate\Support\Str;
  * Seeds the form-builder layer for DevSeeder: 16 system form_templates per
  * org, one FormSchema per event, the canonical 16-field registration set,
  * and a realistic batch of FormSubmissions for approved/applied/no_show
- * persons (same rule as the forms:migrate-legacy-data command).
+ * persons.
  *
  * Callers MUST wrap this in ActivityLog::suppressed() — every field create
  * would otherwise fire a logFieldChange("created") entry.
@@ -174,7 +174,6 @@ final class FormBuilderDevSeeder
     /**
      * For each person with status ∈ applied/approved/no_show on this event,
      * create one FormSubmission with a realistic handful of FormValues.
-     * Status follows the same rule as MigrateLegacyFormsData.
      */
     public static function seedSubmissionsForEvent(Event $event, FormSchema $schema): int
     {