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/components/views/board-view/constants.ts

@@ -0,0 +1,22 @@
+import { Feature } from "@/store/app-store";
+
+export type ColumnId = Feature["status"];
+
+export const COLUMNS: { id: ColumnId; title: string; colorClass: string }[] = [
+  { id: "backlog", title: "Backlog", colorClass: "bg-[var(--status-backlog)]" },
+  {
+    id: "in_progress",
+    title: "In Progress",
+    colorClass: "bg-[var(--status-in-progress)]",
+  },
+  {
+    id: "waiting_approval",
+    title: "Waiting Approval",
+    colorClass: "bg-[var(--status-waiting)]",
+  },
+  {
+    id: "verified",
+    title: "Verified",
+    colorClass: "bg-[var(--status-success)]",
+  },
+];