feat(provenance): provenance store (cached image/post lookups)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/stores/provenance.js

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+import { defineStore } from 'pinia'
+import { ref } from 'vue'
+import { useApi } from '../composables/useApi.js'
+
+// Provenance is its own system — this store is deliberately independent
+// of the modal/tags stores (see project_provenance_separation).
+export const useProvenanceStore = defineStore('provenance', () => {
+  const api = useApi()
+
+  const imageCache = ref({})  // id -> { loading, error, entries|null }
+  const postCache = ref({})   // id -> { loading, error, data|null }
+
+  async function loadForImage(id) {
+    const cur = imageCache.value[id]
+    if (cur && (cur.loading || cur.entries !== null)) return
+    imageCache.value[id] = { loading: true, error: null, entries: null }
+    try {
+      const body = await api.get(`/api/provenance/image/${id}`)
+      imageCache.value[id] =
+        { loading: false, error: null, entries: body.provenance }
+    } catch (e) {
+      imageCache.value[id] =
+        { loading: false, error: e.message, entries: null }
+    }
+  }
+
+  async function loadForPost(id) {
+    const cur = postCache.value[id]
+    if (cur && (cur.loading || cur.data !== null)) return
+    postCache.value[id] = { loading: true, error: null, data: null }
+    try {
+      const body = await api.get(`/api/provenance/post/${id}`)
+      postCache.value[id] = { loading: false, error: null, data: body }
+    } catch (e) {
+      postCache.value[id] = { loading: false, error: e.message, data: null }
+    }
+  }
+
+  function imageProv(id) { return imageCache.value[id] || null }
+  function postInfo(id) { return postCache.value[id] || null }
+
+  return { imageCache, postCache, loadForImage, loadForPost,
+           imageProv, postInfo }
+})

frontend/test/provenance.spec.js

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+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest'
+import { setActivePinia, createPinia } from 'pinia'
+import { useProvenanceStore } from '../src/stores/provenance.js'
+
+function stubFetch(handler) {
+  globalThis.fetch = vi.fn(async (url, init) => {
+    const { status, body } = handler(url, init)
+    return {
+      ok: status >= 200 && status < 300,
+      status,
+      statusText: String(status),
+      text: async () => (body == null ? '' : JSON.stringify(body))
+    }
+  })
+}
+
+describe('provenance store', () => {
+  beforeEach(() => setActivePinia(createPinia()))
+  afterEach(() => vi.restoreAllMocks())
+
+  it('loadForImage caches: repeat same id does not refetch', async () => {
+    const store = useProvenanceStore()
+    stubFetch(() => ({ status: 200, body: { image_id: 5, provenance: [] } }))
+    await store.loadForImage(5)
+    await store.loadForImage(5)
+    expect(globalThis.fetch.mock.calls.length).toBe(1)
+    expect(store.imageProv(5).entries).toEqual([])
+  })
+
+  it('loadForImage fetches distinct ids separately', async () => {
+    const store = useProvenanceStore()
+    stubFetch(() => ({
+      status: 200,
+      body: { image_id: 1, provenance: [{ provenance_id: 9 }] }
+    }))
+    await store.loadForImage(1)
+    await store.loadForImage(2)
+    expect(globalThis.fetch.mock.calls.length).toBe(2)
+    expect(store.imageProv(1).entries.length).toBe(1)
+  })
+
+  it('loadForImage records error without throwing', async () => {
+    const store = useProvenanceStore()
+    stubFetch(() => ({ status: 404, body: { error: 'not found' } }))
+    await store.loadForImage(7)
+    expect(store.imageProv(7).error).toBeTruthy()
+    expect(store.imageProv(7).entries).toBe(null)
+  })
+
+  it('loadForPost caches and stores post/source/artist', async () => {
+    const store = useProvenanceStore()
+    stubFetch(() => ({
+      status: 200,
+      body: { post: { id: 3 }, source: { platform: 'patreon' },
+              artist: { name: 'A', slug: 'a' } }
+    }))
+    await store.loadForPost(3)
+    await store.loadForPost(3)
+    expect(globalThis.fetch.mock.calls.length).toBe(1)
+    expect(store.postInfo(3).data.artist.slug).toBe('a')
+  })
+})