feat: sidebar Kanban board + pages Markdown + boutons + et 📚 fonctionnels

- Sidebar: 'Kanban board' affiché avant les 4 sous-vues
- DB: nouvelle table 'pages' (workspace, title, content, parent_section)
- API: POST /board/api/pages, GET/PUT /board/api/pages/{id}
- UI: page_editor.html — éditeur Markdown avec preview live
- UI: boutons + créent une page Markdown, bouton 📚 ouvre la page
- Dashboard: sidebar_data utilise BDD pages + workspace
- board.py: _sidebar_data enrichi (Kanban board + pages DB)

app/db.py

@@ -130,6 +130,16 @@ def init_db():
                 created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
                 UNIQUE(project_owner, project_name, keyword)
             );
+
+            CREATE TABLE IF NOT EXISTS pages (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                workspace TEXT NOT NULL,
+                title TEXT NOT NULL DEFAULT 'New page',
+                content TEXT NOT NULL DEFAULT '',
+                parent_section TEXT DEFAULT 'Private',
+                created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+                updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+            );
         """)
         conn.commit()