feat: manage fruits — full CRUD with images and synonyms (story #02)

Backend: domain structs, FruitRepository interface + pg implementation,
9 Echo v4 handlers (list/get/create/update/delete, image sub-resources),
migration 000002 (fruit_type ENUM, fruits, fruit_synonyms, fruit_images),
route-scoped BodyLimit("5M") for uploads, http.DetectContentType for serving.

Frontend: typed fetch API layer, Pinia setup-style fruitStore, FruitList
(paginated), FruitCreate, and FruitDetail (edit + synonyms editor + image
gallery). 25 backend unit tests + integration test; 18 frontend tests.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/api/fruits.ts

@@ -0,0 +1,136 @@
+export const FRUIT_TYPES = [
+  'Apfelsorten',
+  'Birnensorten',
+  'Quittensorten',
+  'Aprikosen',
+  'Pfirsiche',
+  'Mirabellen',
+  'Renekloden',
+  'Pflaumen',
+  'Zwetschen',
+  'Sauerkirschen',
+  'Süßkirschen',
+  'Brombeeren',
+  'Erdbeeren',
+  'Himbeeren',
+  'Johannisbeeren',
+  'Stachelbeeren',
+  'Wein',
+] as const
+
+export type FruitType = (typeof FRUIT_TYPES)[number]
+
+export interface FruitImage {
+  id: number
+  fruit_id: number
+  filename: string | null
+  image_type: string
+  title: string | null
+  url: string
+  created_at: string
+}
+
+export interface Fruit {
+  id: number
+  name: string
+  osdb_number: string
+  comment: string | null
+  fruit_type: string
+  synonyms: string[]
+  images: FruitImage[]
+  created_at: string
+  updated_at: string
+}
+
+export interface FruitListResponse {
+  items: Fruit[]
+  total: number
+  limit: number
+  offset: number
+}
+
+export interface FruitWriteDTO {
+  name: string
+  osdb_number: string
+  comment?: string | null
+  fruit_type: string
+  synonyms: string[]
+}
+
+export function imageUrl(fruitId: number, imageId: number): string {
+  return `/api/v1/fruits/${fruitId}/images/${imageId}`
+}
+
+async function checkOk(res: Response): Promise<Response> {
+  if (!res.ok) {
+    let msg = `${res.status}`
+    try {
+      const body = await res.json()
+      msg = body.error ?? body.errors?.join(', ') ?? msg
+    } catch {
+      // ignore parse error
+    }
+    const err = new Error(msg) as Error & { status: number }
+    err.status = res.status
+    throw err
+  }
+  return res
+}
+
+export async function listFruits(limit = 50, offset = 0): Promise<FruitListResponse> {
+  const res = await fetch(`/api/v1/fruits?limit=${limit}&offset=${offset}`)
+  return (await checkOk(res)).json()
+}
+
+export async function getFruit(id: number): Promise<Fruit> {
+  const res = await fetch(`/api/v1/fruits/${id}`)
+  return (await checkOk(res)).json()
+}
+
+export async function createFruit(dto: FruitWriteDTO): Promise<Fruit> {
+  const res = await fetch('/api/v1/fruits', {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify(dto),
+  })
+  return (await checkOk(res)).json()
+}
+
+export async function updateFruit(id: number, dto: FruitWriteDTO): Promise<Fruit> {
+  const res = await fetch(`/api/v1/fruits/${id}`, {
+    method: 'PUT',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify(dto),
+  })
+  return (await checkOk(res)).json()
+}
+
+export async function deleteFruit(id: number): Promise<void> {
+  const res = await fetch(`/api/v1/fruits/${id}`, { method: 'DELETE' })
+  await checkOk(res)
+}
+
+export async function listImages(fruitId: number): Promise<FruitImage[]> {
+  const res = await fetch(`/api/v1/fruits/${fruitId}/images`)
+  return (await checkOk(res)).json()
+}
+
+export async function addImage(
+  fruitId: number,
+  file: File,
+  imageType: string,
+  title?: string,
+): Promise<FruitImage> {
+  const form = new FormData()
+  form.append('image', file)
+  form.append('image_type', imageType)
+  if (title) form.append('title', title)
+  // Do NOT set Content-Type — browser sets it with the correct multipart boundary
+  const res = await fetch(`/api/v1/fruits/${fruitId}/images`, { method: 'POST', body: form })
+  return (await checkOk(res)).json()
+}
+
+export async function deleteImage(fruitId: number, imageId: number): Promise<void> {
+  const res = await fetch(`/api/v1/fruits/${fruitId}/images/${imageId}`, { method: 'DELETE' })
+  await checkOk(res)
+}