feat: Update AI rule files

CLAUDE.md

@@ -737,6 +737,26 @@ act -n
 6. **Form structure is three-level** - Section → SubSection → Element (not two-level)
 7. **API generation is automatic** - After modifying OpenAPI spec, run generation commands
 8. **Roles are managed in Keycloak** - Not in the application database
+9. **PDF/HTML export must be re-validated when form elements change**
+   - Any change that touches form element types, options/value storage, visibility conditions, or section spawning can break PDF output.
+   - Always validate **both** HTML and PDF export for a real form instance (including newly spawned sections and newly added text fields with values):
+     - `GET /application-forms/{id}/html`
+     - `GET /application-forms/{id}/pdf`
+   - Verify these render correctly (with saved values):
+     - `TEXTFIELD`, `TEXTAREA`, `DATE`, `TITLE_BODY_TEXTFIELDS`
+     - `SELECT`, `RADIOBUTTON`, `CHECKBOX`, `SWITCH`
+   - If you changed backend filtering or templating, ensure:
+     - Template sections (`isTemplate=true`) remain excluded from export
+     - Spawned sections (`isTemplate=false`, `spawnedFromElementReference` set) are included
+     - Visibility filtering does not drop elements unintentionally (e.g. missing `reference` must not hide elements by default)
+   - Hotspots:
+     - `legalconsenthub-backend/src/main/kotlin/com/betriebsratkanzlei/legalconsenthub/application_form/ApplicationFormFormatService.kt`
+     - `legalconsenthub-backend/src/main/resources/templates/application_form_template.html`
+10. **Keep `CLAUDE.md` current**
+   - If you introduce a change that is worth being documented for future AI prompts (architecture, domain rules, workflows, endpoints, config, auth, generation steps, export logic, multi-tenancy constraints, etc.), update `CLAUDE.md` in the same change set.
+11. **Clean Code: order functions by abstraction (top-down, like a book)**
+   - Put the highest-level, most readable entry points first (public API / primary flows), then progressively lower-level helpers below.
+   - Keep functions at the same level of abstraction grouped together; details should live “later” (below) so the file reads top-to-bottom without jumping around.
 
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