Rename lists -> projects and items -> cards throughout

Project scope shifts from a todo list to a project-management app. This is a
straight terminology rename across code, comments, migrations, tests, and
docs — no behaviour change.

- DB: table todo_lists -> projects, todo_items -> cards, column
  todo_items.list_id -> cards.project_id, indexes renamed. Migrations 003/004
  rewritten in place (destructive; recreate the volume with `down -v`).
- API: /api/lists -> /api/projects, nested /items -> /cards, reorder body
  item_ids -> card_ids, JSON keys list/lists/item/items -> project/projects/
  card/cards, item_count -> card_count, list_id -> project_id, and the
  matching error messages.
- PHP: TodoList/TodoItem Repository + Controller -> Project/Card; shared SQL
  aliases l/i -> p/c.
- Frontend: stores lists.ts/items.ts -> projects.ts/cards.ts (useProjectsStore
  / useCardsStore, MAX_PROJECTS), ListView -> ProjectView, TodoItemRow ->
  CardRow, route /lists/:id -> /projects/:id (name "project"), types TodoList/
  TodoItem -> Project/Card, and all UI copy. CSS .lists*/.list-head* ->
  .projects*/.project-head*, .item* -> .card-row* (kept the generic .card
  panel class), .items -> .cards.
- Product name in the header, PWA manifest, index.html title and package
  descriptions -> "Project Manager" / "Projects".

Backend suite: 37 passing.

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

composer.json

@@ -1,6 +1,6 @@
 {
     "name": "aneurin/php-todo-list",
-    "description": "Simple todo list REST API + SPA (PHP, SQLite)",
+    "description": "Simple project-management REST API + SPA (PHP, SQLite)",
     "type": "project",
     "license": "MIT",
     "require": {