feat: Add canvas gallery with soft delete, snapshots and components

Replace the empty dynamic canvas placeholder with a gallery showing
saved canvases, snapshots and Vue components. Users can create new
canvases, restore snapshots, load components, and manage canvas
toolbar/archive settings from the gallery.

- Backend: soft delete (archive) instead of hard delete, status column
- Frontend: CanvasGallery component with grid, search, settings popover
- Show canvas name in global header when viewing a project canvas
- Remove ProjectsPage (replaced by gallery), clean all references
- MCP tools: project category available on canvas page, update handlers

server/routes/canvas.ts

@@ -7,18 +7,19 @@ function parseCanvas(row: any) {
     is_default: !!row.is_default,
     is_system: !!row.is_system,
     show_in_toolbar: !!row.show_in_toolbar,
+    status: row.status || 'active',
     config: row.config ? JSON.parse(row.config) : null,
     tools: row.tools ? JSON.parse(row.tools) : []
   }
 }
 
 export function handleToolbarCanvas() {
-  const rows = db.query('SELECT * FROM project_canvas WHERE show_in_toolbar = 1 ORDER BY toolbar_order ASC, name ASC').all()
+  const rows = db.query('SELECT * FROM project_canvas WHERE show_in_toolbar = 1 AND (status = \'active\' OR status IS NULL) ORDER BY toolbar_order ASC, name ASC').all()
   return jsonResponse((rows as any[]).map(parseCanvas))
 }
 
 export function handleDefaultCanvas() {
-  const row = db.query('SELECT * FROM project_canvas WHERE is_default = 1 LIMIT 1').get() as any
+  const row = db.query('SELECT * FROM project_canvas WHERE is_default = 1 AND (status = \'active\' OR status IS NULL) LIMIT 1').get() as any
   if (!row) {
     return jsonResponse({ hasDefault: false })
   }
@@ -27,7 +28,10 @@ export function handleDefaultCanvas() {
 
 export async function handleCanvas(req: Request) {
   if (req.method === 'GET') {
-    const rows = db.query('SELECT * FROM project_canvas ORDER BY is_system DESC, is_default DESC, name ASC').all()
+    const url = new URL(req.url)
+    const includeArchived = url.searchParams.get('include_archived') === 'true'
+    const whereClause = includeArchived ? '' : 'WHERE (status = \'active\' OR status IS NULL)'
+    const rows = db.query(`SELECT * FROM project_canvas ${whereClause} ORDER BY is_system DESC, is_default DESC, name ASC`).all()
     return jsonResponse((rows as any[]).map(parseCanvas))
   }
 
@@ -129,6 +133,7 @@ export async function handleCanvasById(req: Request, id: string, action?: string
       if (body.show_in_toolbar !== undefined) { updates.push('show_in_toolbar = ?'); values.push(body.show_in_toolbar ? 1 : 0) }
       if (body.toolbar_icon !== undefined) { updates.push('toolbar_icon = ?'); values.push(body.toolbar_icon) }
       if (body.toolbar_order !== undefined) { updates.push('toolbar_order = ?'); values.push(body.toolbar_order) }
+      if (body.status !== undefined) { updates.push('status = ?'); values.push(body.status) }
     }
 
     if (updates.length > 0) {
@@ -141,13 +146,13 @@ export async function handleCanvasById(req: Request, id: string, action?: string
     return jsonResponse({ success: true, id })
   }
 
-  // DELETE /api/canvas/:id
+  // DELETE /api/canvas/:id (soft delete - archive)
   if (req.method === 'DELETE' && !action) {
     const canvas = db.query('SELECT is_system FROM project_canvas WHERE id = ?').get(id) as { is_system: number } | null
     if (canvas?.is_system) {
       return errorResponse('Cannot delete system canvas', 403)
     }
-    db.run('DELETE FROM project_canvas WHERE id = ?', [id])
+    db.run('UPDATE project_canvas SET status = \'archived\', show_in_toolbar = 0, updated_at = CURRENT_TIMESTAMP WHERE id = ?', [id])
     return jsonResponse({ success: true })
   }