Add stage 4: frontend lists view + enforce 100-list cap

API: GET /api/lists is now ordered alphabetically (COLLATE NOCASE) by title
with no other option, and TodoListController rejects a create past 100 lists
per owner with 409. New TodoListRepository::countForOwner.

Frontend: HomeView replaces the placeholder with the user's lists (rendered in
API order) and a create form (title + optional description). New Pinia lists
store fetches and creates, re-fetching after a create so the new list sorts
into place; it is reset on logout. Form disables and explains at 100 lists;
create errors surface inline. Neutral .badge with a .badge--warn variant;
dropped the unused .facts styles.

Tests: alphabetical ordering and the 100-list cap. Suite: 17 passing.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/src/types.ts

@@ -12,6 +12,17 @@ export interface AuthResponse {
   expires_at: string
 }
 
+export interface TodoList {
+  id: number
+  title: string
+  description: string
+  owner_id: number
+  item_count: number
+  completed_count: number
+  created_at: string
+  updated_at: string
+}
+
 /** Shape of every error body returned by the API. */
 export interface ApiErrorBody {
   error: {