feat(blueprints): refactor investigation-summary and report page layouts

Investigation Summary:
- Reorganize fields for better UX (cover moved up)
- Enhance video system with preview and URL fields
- Convert synthesis field to writer with formatting options
- Change team field to multiselect with database query
- Adjust field widths for better layout

Report:
- Simplify page layout and column structure
- Make cover image required
- Remove metadata tab (fields integrated in main tab)
- Add gallery block to available blocks
- Move authors field to main content area

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

site/blueprints/pages/investigation-summary.yml

@@ -16,6 +16,15 @@ tabs:
                 display: DD / MM / YYYY
                 default: today
                 width: 1/2
+              cover:
+                label: Visuel de couverture
+                type: files
+                multiple: false
+                layout: cards
+                image:
+                  ratio: 12/7
+                  cover: true
+                help: Image utilisée dans les listes d'enquêtes
           reportSection:
             label: Rapport
             type: pages
@@ -27,18 +36,10 @@ tabs:
             type: writer
             nodes: false
             buttons: false
-          cover:
-            label: Visuel de couverture
-            type: files
-            multiple: false
-            layout: cards
-            image:
-              ratio: 12/7
-              cover: true
-            help: Image utilisée dans les listes d'enquêtes
           heroType:
             label: Type de hero
             type: select
+            default: image
             options:
               image: Image simple
               video: Vidéo
@@ -49,25 +50,40 @@ tabs:
             type: files
             multiple: true
             layout: cards
+            width: 1/3
             when:
               heroType: image
-          videoExtractUrl:
-            label: URL vidéo d'extrait (autoplay)
-            type: url
+          videoPreview:
+            label: Preview
+            type: files
+            multiple: false
+            help: Extrait joué en autoplay muet.
+            width: 1/3
             when:
               heroType: video
-            width: 1/2
-          videoFullUrl:
+          videoUrl:
             label: URL vidéo complète (YouTube embed)
             type: url
+            width: 1/3
             when:
               heroType: video
-            width: 1/2
           synthesis:
             label: Synthèse
-            type: textarea
+            type: writer
             size: large
-            buttons: false
+            headings:
+              - 4
+            nodes:
+              - heading
+              - bulletlist
+              - orderedlist
+            marks:
+              - bold
+              - italic
+              - underline
+              - link
+              - '|'
+              - clear
   metadataTab:
     label: Métadonnées
     icon: table
@@ -106,13 +122,13 @@ tabs:
         type: multiselect
         options: query
         query: page('database').keywords.split
-        width: 1/2
+        width: 1/3
       methodologies:
         label: Méthodologies
         options: query
         query: page('database').methodologies.split
         type: multiselect
-        width: 1/2
+        width: 1/3
       partners:
         label: Partenaires
         type: structure
@@ -126,7 +142,9 @@ tabs:
             type: url
       team:
         label: Équipe Index
-        type: tags
+        type: multiselect
+        options: query
+        query: page('database').team.split
         width: 1/2
       relatedInvestigations:
         label: Enquêtes en lien