reset to setup module state

Remove Task Manager implementation to match `# Setup module` in module.md.
Backend src/ reduced to Kernel.php + empty Entity/, all migrations deleted,
database dropped and recreated. Frontend components/views/services/stores
removed, App.vue/router/style.css reduced to skeletons. CLAUDE.md shortened
to Setup-stand. Old backend/plan.md, plan2.md removed.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/stores/categories.js

@@ -1,34 +0,0 @@
-import { defineStore } from 'pinia'
-import { ref } from 'vue'
-import * as api from '../services/api'
-
-export const useCategoriesStore = defineStore('categories', () => {
-  const items = ref([])
-  const loaded = ref(false)
-
-  async function fetchCategories(force = false) {
-    if (loaded.value && !force) return
-    items.value = await api.getCategories()
-    loaded.value = true
-  }
-
-  async function addCategory(data) {
-    const category = await api.createCategory(data)
-    items.value.push(category)
-    return category
-  }
-
-  async function editCategory(id, data) {
-    const updated = await api.updateCategory(id, data)
-    const index = items.value.findIndex((c) => c.id === id)
-    if (index !== -1) items.value[index] = updated
-    return updated
-  }
-
-  async function removeCategory(id) {
-    await api.deleteCategory(id)
-    items.value = items.value.filter((c) => c.id !== id)
-  }
-
-  return { items, loaded, fetchCategories, addCategory, editCategory, removeCategory }
-})