feat(provenance): gallery store post_id filter (mutually exclusive with tag_id)

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

frontend/src/stores/gallery.js

@@ -10,7 +10,7 @@ export const useGalleryStore = defineStore('gallery', () => {
   const nextCursor = ref(null)
   const loading = ref(false)
   const error = ref(null)
-  const filter = ref({ tag_id: null })
+  const filter = ref({ tag_id: null, post_id: null })
 
   const timelineBuckets = ref([])
   const timelineLoading = ref(false)
@@ -30,8 +30,7 @@ export const useGalleryStore = defineStore('gallery', () => {
     error.value = null
     const myId = ++inflightId
     try {
-      const params = { limit: 50 }
-      if (filter.value.tag_id) params.tag_id = filter.value.tag_id
+      const params = { limit: 50, ...activeFilterParam() }
       if (nextCursor.value) params.cursor = nextCursor.value
       const body = await api.get('/api/gallery/scroll', { params })
       if (myId !== inflightId) return  // stale response
@@ -48,7 +47,7 @@ export const useGalleryStore = defineStore('gallery', () => {
   async function loadTimeline() {
     timelineLoading.value = true
     try {
-      const params = filter.value.tag_id ? { tag_id: filter.value.tag_id } : {}
+      const params = activeFilterParam()
       timelineBuckets.value = await api.get('/api/gallery/timeline', { params })
     } finally {
       timelineLoading.value = false
@@ -56,8 +55,7 @@ export const useGalleryStore = defineStore('gallery', () => {
   }
 
   async function jumpTo(year, month) {
-    const params = { year, month }
-    if (filter.value.tag_id) params.tag_id = filter.value.tag_id
+    const params = { year, month, ...activeFilterParam() }
     const body = await api.get('/api/gallery/jump', { params })
     if (body.cursor) {
       images.value = []
@@ -67,8 +65,22 @@ export const useGalleryStore = defineStore('gallery', () => {
     }
   }
 
+  function activeFilterParam() {
+    if (filter.value.tag_id) return { tag_id: filter.value.tag_id }
+    if (filter.value.post_id) return { post_id: filter.value.post_id }
+    return {}
+  }
+
   function setTagFilter(tagId) {
     filter.value.tag_id = tagId
+    filter.value.post_id = null
+    loadInitial()
+    loadTimeline()
+  }
+
+  function setPostFilter(postId) {
+    filter.value.post_id = postId
+    filter.value.tag_id = null
     loadInitial()
     loadTimeline()
   }
@@ -79,7 +91,7 @@ export const useGalleryStore = defineStore('gallery', () => {
   return {
     images, dateGroups, hasMore, isEmpty, loading, error,
     filter, timelineBuckets, timelineLoading,
-    loadInitial, loadMore, loadTimeline, jumpTo, setTagFilter
+    loadInitial, loadMore, loadTimeline, jumpTo, setTagFilter, setPostFilter
   }
 })