chore: YAML-Schemas in Dateiköpfe, tibi-types auf 4c55f82

- yaml-language-server-Schema direkt in jeder api-YAML statt
  .vscode/yaml.schemas-Mapping (exakter pro Datei, kein Glob-Rätsel)
- erweiterte meta.agent-Doku in den Collections
- tibi-types-Submodul auf 4c55f82 (meta.agent- + meta.query-Schemas)

api/collections/content.yml

@@ -1,3 +1,4 @@
+# yaml-language-server: $schema=../../tibi-types/schemas/config/collection.schema.json
 ########################################################################
 # Content collection — CMS-managed pages with pagebuilder blocks
 ########################################################################
@@ -38,8 +39,8 @@ meta:
       translationKey: "required, e.g. home/ueber-uns/kontakt; unique per lang"
       blocks: "type selects visible fields via dependsOn $parent.type"
     examples: [{ name: "Startseite", path: "/", lang: "de", translationKey: "home", active: true }]
-    workflows: ["filter before create (path+lang) to stay idempotent; 409 means exists", "after PUT/DELETE verify /de and /api/content?lookup; SSR invalidates via clear_cache hooks"]
-    hints: ["richtext image only renders when _lookup.image.file.src exists", "hero fallback is gradient when no image"]
+    workflows: ["filter before create (path+lang) to stay idempotent; 409 means exists", "after PUT/DELETE verify /de and anonymous SSR HTML (window.__SSR_CACHE__: navigation count>0, heroImage/image with _lookup); PAT-only lookup success is NOT sufficient; SSR invalidates via clear_cache hooks"]
+    hints: ["richtext image only renders when _lookup.image.file.src exists", "hero fallback is gradient when no image", "images/nav invisible publicly until their medialib/navigation docs carry active:true (verified incident 2026-10-05)"]
 
 hooks:
   get: