QA plans al sugerir HU + cancel analisis + datepicker shadcn

- project-analyzer: saveAsDrafts genera QA plan por cada HU sugerida
- DashboardView: cancelAnalysis con AbortController + mensaje limpio
- HuDrafts: DatePicker con Calendar + Popover (shadcn-vue)
- HuDrafts: formulario dinámico segun tipo (Epic vs HU/Feature/etc)
- components/ui: Popover + Calendar creados
- qa_plans: tabla separada (cubre drafts + user_stories existentes)

package.json

@@ -11,6 +11,7 @@
     "tauri": "npx tauri"
   },
   "dependencies": {
+    "@internationalized/date": "^3.12.2",
     "@lucide/vue": "^1.16.0",
     "@tabler/icons-vue": "^3.44.0",
     "@tailwindcss/vite": "^4.3.0",