VITEC headless v14: 5-bug fix unifies plugin renderers + cleanup

Resolves a cascade of TYPO3 v14 breaking changes that left every VITEC
plugin's JSON output silently empty:

1. `list_type` column dropped — all renderer page-discovery queries now
   filter by `CType = 'vitec_X'`.
2. `#[AsAllowedCallable]` attribute added to every public render() —
   without it v14 throws AllowedCallableException, which headless
   silently filters via its "Oops, an error occurred!" guard.
3. `$GLOBALS['TSFE']->id` is null inside JSON cObj context — page id
   now read from the `frontend.page.information` request attribute
   (TSFE fallback kept for legacy entry points).
4. page.tsconfig wizard items migrated to `CType = vitec_X` directly
   (legacy `CType=list, list_type=...` no longer exists in v14).
5. ContainerChildrenProcessor + ContentElementResolver dispatch the
   PLUGIN_RENDERERS map by CType (primary) with list_type fallback.

Beyond the bug fix this commit also contains:
- Datasheets renderer rewritten to "products with newest datasheet"
  semantics (filtered via Download.hideondatasheets).
- New vitec/card content block — multi-purpose card with backend
  preview and layout/background/aspect/alignment/border/shadow options.
- New vitec_container CType (b13 single-column container, FlexForm
  cssClass propagated into the JSON envelope).
- ContentElementResolver service for contentelement/contentelementcta
  link resolution; ContainerChildrenProcessor for nested plugin
  resolution inside b13 containers.
- Vitecset setup.typoscript: ContentElement import moved to top so
  lib.contentElement is defined before VITEC's tt_content blocks.
- Cleanup: 98 .bak.<timestamp> debugging backups removed; *.bak.* and
  /public/_assets_install/ added to .gitignore.

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

packages/vitec/Configuration/TypoScript/Headless/vitec_containers.typoscript.bak.20260518150609

@@ -1,89 +0,0 @@
-# =============================================================================
-# VITEC container content elements — self-contained JSON rendering
-# Children collected via Evomedien\Vitec\DataProcessing\ContainerChildrenProcessor
-# (exception-safe; returns [] on any error, never crashes the outer CE).
-# =============================================================================
-
-tt_content.vitec_cols_50_50 = JSON
-tt_content.vitec_cols_50_50 {
-    fields {
-        id = INT
-        id.field = uid
-        type = TEXT
-        type.field = CType
-        colPos = INT
-        colPos.field = colPos
-
-        categories = COA
-        categories {
-            10 = CONTENT
-            10 {
-                table = sys_category
-                select {
-                    pidInList = root
-                    selectFields = sys_category.title
-                    join = sys_category_record_mm on sys_category_record_mm.uid_local = sys_category.uid
-                    where {
-                        field = uid
-                        wrap = AND sys_category_record_mm.tablenames = 'tt_content' AND sys_category_record_mm.uid_foreign=|
-                    }
-                }
-                renderObj = TEXT
-                renderObj {
-                    field = title
-                    wrap = |###BREAK###
-                }
-            }
-            stdWrap.split {
-                token = ###BREAK###
-                cObjNum = 1 |*|2|*| 3
-                1 {
-                    current = 1
-                    stdWrap.wrap = |
-                }
-                2 {
-                    current = 1
-                    stdWrap.wrap = ,|
-                }
-                3 {
-                    current = 1
-                    stdWrap.wrap = |
-                }
-            }
-        }
-
-        appearance = JSON
-        appearance {
-            fields {
-                layout = TEXT
-                layout.field = layout
-                frameClass = TEXT
-                frameClass.field = frame_class
-                spaceBefore = TEXT
-                spaceBefore.field = space_before_class
-                spaceAfter = TEXT
-                spaceAfter.field = space_after_class
-            }
-        }
-
-        header = TEXT
-        header.field = header
-        subheader = TEXT
-        subheader.field = subheader
-        tx_vitec_bg_variant = TEXT
-        tx_vitec_bg_variant.field = tx_vitec_bg_variant
-
-        items = JSON
-        items {
-            dataProcessing {
-                10 = Evomedien\Vitec\DataProcessing\ContainerChildrenProcessor
-                10.as = items
-            }
-        }
-    }
-}
-
-tt_content.vitec_cols_33_33_33 =< tt_content.vitec_cols_50_50
-tt_content.vitec_cols_25_25_25_25 =< tt_content.vitec_cols_50_50
-tt_content.vitec_cols_66_33 =< tt_content.vitec_cols_50_50
-tt_content.vitec_cols_33_66 =< tt_content.vitec_cols_50_50