feat: menu New page (Empty/Database/Kanban) + slash commands / dans l'éditeur

- Topbar bouton New ▾ avec dropdown: Empty page, Database, Kanban board
- page_editor: commandes slash / (/h1, /h2, /list, /todo, /code, /table, /quote...)
- Fonctions JS: createEmptyPage, createDatabase, createBoard
- State showNewPageMenu dans Alpine.js

app/templates/page_editor.html

@@ -36,10 +36,11 @@
       <div style="padding:4px 12px; background:var(--bg-tertiary); font-size:12px; color:var(--text-dim);">Markdown</div>
       <textarea x-ref="editor" x-model="content"
                 @input="autoSave()"
+                @keydown="handleSlash($event)"
                 style="flex:1; width:100%; min-height:400px; background:var(--bg-secondary);
                        border:none; padding:12px; color:var(--text-primary); font-family:var(--font-mono);
                        font-size:13px; line-height:1.6; resize:none; outline:none; tab-size:2;"
-                placeholder="Start writing in Markdown..."></textarea>
+                placeholder="Type '/' for commands, or start writing in Markdown..."></textarea>
     </div>
     <!-- Preview -->
     <div style="flex:1; border-left:1px solid var(--border); display:flex; flex-direction:column;">
@@ -145,7 +146,43 @@
       },
       saveTitle(newTitle) {
         fetch(`/board/api/pages/{{ page.id }}?title=${encodeURIComponent(newTitle)}`, { method: 'PUT' });
-      }
+      },
+      handleSlash(e) {
+        if (e.key === '/' && !e.ctrlKey && !e.metaKey) {
+          const el = this.$refs.editor;
+          const cursor = el.selectionStart;
+          const lineStart = this.content.lastIndexOf('\n', cursor - 1) + 1;
+          const charsBefore = this.content.substring(lineStart, cursor);
+          // Only trigger at start of line or after whitespace
+          if (charsBefore.trim() === '') {
+            e.preventDefault();
+            this.content = this.content.substring(0, cursor) + '/';
+            // Simple menu: insert template after short delay
+            const cmd = prompt('Slash command:\n  /h1 - Heading 1\n  /h2 - Heading 2\n  /h3 - Heading 3\n  /bold - Bold\n  /list - Bullet list\n  /num - Numbered list\n  /code - Code block\n  /quote - Quote\n  /todo - To-do list\n  /table - Table\n  /divider - Divider\n  /link - Link\n  /img - Image\n  /date - Date');
+            if (!cmd) { this.content = this.content.substring(0, cursor); return; }
+            const templates = {
+              h1: '# ',
+              h2: '## ',
+              h3: '### ',
+              bold: '**bold text**',
+              list: '- ',
+              num: '1. ',
+              code: '```\ncode\n```',
+              quote: '> ',
+              todo: '- [ ] ',
+              table: '| Col 1 | Col 2 |\n|-------|-------|\n| | |',
+              divider: '---\n',
+              link: '[text](url)',
+              img: '![alt](url)',
+              date: new Date().toISOString().slice(0, 10),
+            };
+            const insert = templates[cmd.replace('/','')] || '';
+            const before = this.content.substring(0, cursor);
+            this.content = before + insert + this.content.substring(cursor + 1);
+            setTimeout(() => { el.focus(); el.selectionStart = el.selectionEnd = before.length + insert.length; }, 50);
+          }
+        }
+      },
     };
   }
 </script>