refactor(board-view): reorganize into modular folder structure

- Extract board-view into organized subfolders following new pattern:
  - components/: kanban-card, kanban-column
  - dialogs/: all dialog and modal components (8 files)
  - hooks/: all board-specific hooks (10 files)
  - shared/: reusable components between dialogs (model-selector, etc.)
- Rename all files to kebab-case convention
- Add barrel exports (index.ts) for clean imports
- Add docs/folder-pattern.md documenting the folder structure
- Reduce board-view.tsx from ~3600 lines to ~490 lines

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

apps/app/src/lib/utils.ts

@@ -25,3 +25,13 @@ export function getModelDisplayName(model: AgentModel | string): string {
   };
   return displayNames[model] || model;
 }
+
+/**
+ * Truncate a description string with ellipsis
+ */
+export function truncateDescription(description: string, maxLength = 50): string {
+  if (description.length <= maxLength) {
+    return description;
+  }
+  return `${description.slice(0, maxLength)}...`;
+}