fix: bouton delete cassé + preview PDF cliquable + icônes distinctes FlowDeck vs upload

1. Delete: ev.target pouvait être un noeud texte (emoji 🗑)
   → Text.closest() n'existe pas → handleTreeAction échouait.
   Fix: fallback sur ev.target.parentElement.closest().

2. Preview PDF: ajout lien 'Open viewer →' vers /pages/{id}
   (le viewer standalone rend le PDF dans une iframe).

3. Icônes distinctes:
   - Pages FlowDeck (content_format='blocks'/'markdown') → 📝
   - Fichiers uploadés → icône basée sur l'extension
   - _fileIcon() accepte contentFormat, propage depuis l'API tree
   - Appliqué dans sidebar (board.py) + page workspace (x-for + renderChildren)

app/routers/board.py

@@ -140,9 +140,12 @@ def _build_page_tree(conn, parent_id: int | None, ws_key: str, depth: int = 0, m
     return items
 
 
-def _file_icon(name: str) -> str:
+def _file_icon(name: str, content_format: str = "") -> str:
     """Map file extension to emoji icon."""
     import re
+    # FlowDeck internal pages (no extension)
+    if content_format and content_format != 'file':
+        return '📝'
     n = name.lower()
     if re.search(r'\.(png|jpe?g|gif|webp|svg|bmp|ico)$', n): return '🖼️'
     if n.endswith('.pdf'): return '📕'
@@ -169,7 +172,7 @@ def _load_workspace_pages(ws_cookie: str) -> list:
         ws_id = int(ws_cookie)
         with get_conn() as conn:
             rows = conn.execute(
-                "SELECT id, title, parent_section FROM pages WHERE workspace_id=? AND parent_id IS NULL ORDER BY created_at DESC",
+                "SELECT id, title, parent_section, content_format FROM pages WHERE workspace_id=? AND parent_id IS NULL ORDER BY created_at DESC",
                 (ws_id,),
             ).fetchall()
         items = []
@@ -179,7 +182,7 @@ def _load_workspace_pages(ws_cookie: str) -> list:
             items.append({
                 "db_id": r["id"], "name": title,
                 "id": f"page/{r['id']}",
-                "icon": "📁" if is_folder else _file_icon(title),
+                "icon": "📁" if is_folder else _file_icon(title, r["content_format"]),
                 "is_folder": is_folder,
                 "children": _load_children(r["id"]),
             })
@@ -192,7 +195,7 @@ def _load_children(parent_id: int) -> list:
     """Recursively load children of a page."""
     with get_conn() as conn:
         rows = conn.execute(
-            "SELECT id, title, parent_section FROM pages WHERE parent_id=? ORDER BY created_at",
+            "SELECT id, title, parent_section, content_format FROM pages WHERE parent_id=? ORDER BY created_at",
             (parent_id,),
         ).fetchall()
     children = []
@@ -202,7 +205,7 @@ def _load_children(parent_id: int) -> list:
         children.append({
             "db_id": r["id"], "name": title,
             "id": f"page/{r['id']}",
-            "icon": "📁" if is_folder else _file_icon(title),
+            "icon": "📁" if is_folder else _file_icon(title, r["content_format"]),
             "is_folder": is_folder,
             "children": _load_children(r["id"]),
         })