docs(forms): SCHEMA crosswalk, foundation concept page, getting-started + migration playbook, copy catalogue init

SCHEMA.md
- New §3.5.12 "Form Builder" with the legacy-tables-retained note
  placed prominently directly under the section header (per S1 wrap-up
  Path 3 decision: Phase 8 deferred to S2).
- Crosswalk: every legacy volunteer_profiles column → its new home
  (user_profiles columns vs form_fields vs person_tags).
- Summary table for the 13 new tables with one-line purpose + ARCH §
  pointer each.
- Activity log strategy and multi-tenancy discipline noted.
- §3.5.4 marked SUPERSEDED with a pointer to the new section.

/dev-docs/form-builder-migration-playbook.md (new)
- Operator runbook for forms:migrate-legacy-data on real legacy data.
- Pre-flight audit, dry-run, migrate, verify, spot-check, rollback
  paths spelled out. Same legacy-tables-retained note prominently.

/dev-docs/form-builder-getting-started.md (new)
- Developer onboarding. Mental model, code samples for creating a
  schema/field/submission/value, adding a new subject type, registering
  a custom field type, suppressing activity log via
  App\Support\ActivityLog::suppressed.

/dev-docs/COPY_CATALOGUE.md (new)
- Seeded verbatim from ARCH §30 (naming conventions, tooltip catalogue,
  warning catalogue) with a header explaining purpose, growth strategy,
  and the per-PR update workflow.

/docs/organizer/forms/concepts/wat-is-een-formulier.md (new VitePress)
- Dutch, informal je/jij. Follows /docs/.templates/concept-page.md.
- Three example use-cases: vrijwilligersregistratie, artist advance,
  incidentrapportage. Light foundation; depth arrives in S2-S5.

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

dev-docs/SCHEMA.md

@@ -669,6 +669,13 @@ $effectiveDate       = $shift->end_date          ?? $shift->timeSlot->date;
 
 ## 3.5.4 Volunteer Profile & History
 
+> **SUPERSEDED by S1 of the form-builder refactor.** The old
+> `volunteer_profiles` table was a planning placeholder that was never
+> physically created. It has been split: user-universal columns moved
+> to the new `user_profiles` table (§3.5.12), and event-variable / skill
+> columns moved to `form_fields` and `person_tags`. See §3.5.12 for the
+> new structure and the column-by-column crosswalk.
+
 ### `volunteer_profiles`
 
 | Column                    | Type            | Notes                                 |
@@ -1924,3 +1931,59 @@ Immutable audit record of every email sent. No soft deletes.
 **Indexes:** `(organisation_id, created_at)`, `(recipient_email, created_at)`, `(template_type, status)`, `(event_id)`, `(person_id)`  
 **Relations:** `belongsTo` organisation (nullable), event (nullable), person (nullable), user (nullable), triggeredBy → user  
 **Soft delete:** no — immutable audit table
+
+---
+
+## 3.5.12 Form Builder
+
+> See `/dev-docs/ARCH-FORM-BUILDER.md` v1.2 for the authoritative
+> specification. This SCHEMA.md section is a summary only and will be
+> fully rewritten at the end of S6.
+>
+> **Legacy tables retained intentionally.** The tables
+> `registration_form_fields`, `person_field_values`, and
+> `registration_field_templates` remain in the schema through end of S1.
+> They are dropped atomically in the first S2 commit together with the
+> removal of legacy controllers, services, requests, resources, policies,
+> and routes. DevSeeder and FormBuilderDevSeeder no longer write to them;
+> they hold zero rows in dev but the schema is preserved for environments
+> with real legacy data that will be migrated via
+> `forms:migrate-legacy-data`.
+
+**Crosswalk: legacy `volunteer_profiles` → new locations**
+
+| Legacy column                  | New location                                    |
+| ------------------------------ | ----------------------------------------------- |
+| `bio`                          | `user_profiles.bio`                             |
+| `photo_url`                    | `user_profiles.photo_url`                       |
+| `tshirt_size`                  | `form_fields` (Pattern B, per event)            |
+| `first_aid`                    | `person_tags` (system-seeded, S3)               |
+| `driving_licence`              | `person_tags` (system-seeded, S3)               |
+| `allergies`                    | `form_fields` (Pattern B, per event)            |
+| `access_requirements`          | `form_fields` (Pattern B, per event)            |
+| `emergency_contact_name`       | `user_profiles.emergency_contact_name`          |
+| `emergency_contact_phone`      | `user_profiles.emergency_contact_phone`         |
+| `reliability_score`            | `user_profiles.reliability_score`               |
+| `is_ambassador`                | `user_profiles.is_ambassador`                   |
+
+### New tables (S1)
+
+| Table | Purpose |
+| --- | --- |
+| `user_profiles` | User-universal profile (bio, photo, emergency contact, reliability_score, is_ambassador, opaque settings JSON). 1:1 with `users`, auto-created by `UserObserver`. ARCH §4.13. |
+| `form_schemas` | Form definition. Polymorphic owner (event / user_profile / artist / company / null). Carries purpose, submission_mode, is_published, public_token, schema_snapshot policy, freeze_on_submit, retention/consent. ARCH §4.1. |
+| `form_schema_sections` | Optional sections within a schema (used when `section_level_submit=true`). ARCH §4.8. |
+| `form_field_library` | Reusable cross-schema field definitions. ARCH §4.7. |
+| `form_fields` | Field within a schema. `field_type` stored as string (custom types via `CustomFieldTypeRegistry`). Carries binding (Pattern A/B/C), is_filterable, is_pii, conditional_logic, value_storage_hint. ARCH §4.2. |
+| `form_submissions` | One submission per `(schema, subject)`. Polymorphic subject. Carries status, review_status, schema_snapshot copy, submission lifecycle timestamps, search_index. ARCH §4.3. |
+| `form_submission_section_statuses` | Per-section status when `section_level_submit=true`. ARCH §4.9. |
+| `form_submission_delegations` | "X fills in this submission on behalf of Y". ARCH §4.10. |
+| `form_values` | EAV row per `(submission, field)`. Integer AI PK for fast joins. Typed columns (value_indexed/number/date/bool) populated by `FormValueObserver`. ARCH §4.4. |
+| `form_value_options` | Filter pivot for multi-value fields (MULTISELECT/CHECKBOX_LIST/TAG_PICKER). Rebuilt by observer. ARCH §4.5. |
+| `form_templates` | Org-scoped reusable schema snapshots. `is_system` for shipped templates. ARCH §4.6. |
+| `form_schema_webhooks` | Webhook subscriptions per schema. URL/secret encrypted via Eloquent cast. ARCH §4.11. |
+| `form_webhook_deliveries` | Webhook delivery audit + retry queue. ARCH §4.12. |
+
+**Activity log strategy:** explicit calls via `FormSchema::logSchemaChange()` and `FormField::logFieldChange()` — no `LogsActivity` trait (would produce noise). Only impactful events logged (publish toggle, purpose change, binding change, is_pii toggle, etc.). Bulk-fixture suppression via `App\Support\ActivityLog::suppressed(fn() => …)` which flips `config('activitylog.enabled')` for the callback.
+
+**Multi-tenancy:** `OrganisationScope` applied on `FormSchema`, `FormTemplate`, `FormFieldLibrary`. Other form-builder tables inherit isolation through their parent schema; `FormSchemaWebhook` documents this discipline explicitly via a docblock warning to never query directly without an eager constraint.