feat: runtime feature flags, upload/download, RAW decoding

Adds Redis-backed feature flags for vision stages with admin UI toggles
and manual backfill trigger, photo upload and download routers with
frontend upload modal, and rawpy-based RAW decoding with JPEG fallback
for misnamed DNGs. Fixes pgvector serialization, is_trashed filter, and
naive-datetime bind in incremental duplicate regrouping; bumps Celery
time limits on regroup tasks beyond the 5-minute default.

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

frontend/src/components/heaps/HeapsPanel.tsx

@@ -11,12 +11,13 @@ import {
   Copy,
   Trash2,
   Users,
+  Download as DownloadIcon,
 } from 'lucide-react'
 import clsx from 'clsx'
 import { useMutation, useQueryClient } from '@tanstack/react-query'
 import { useHeapsQuery, HEAPS_QUERY_KEY } from '../../hooks/useHeapsQuery'
 import { useSharedHeapsQuery } from '../../hooks/useSharingQueries'
-import { heaps as heapsApi, type Heap } from '../../services/api'
+import { heaps as heapsApi, downloads, type Heap } from '../../services/api'
 import { useFilterStore } from '../../store/filterStore'
 import { toast } from '../ToastContainer'
 import { PHOTO_DRAG_MIME } from '../timeline/PhotoThumbnail'
@@ -448,6 +449,14 @@ export function HeapsPanel() {
                           setSharingHeap(heap)
                         }}
                       />
+                      <MenuItem
+                        icon={<DownloadIcon className="h-3.5 w-3.5" />}
+                        label="Download as zip"
+                        onClick={() => {
+                          setOpenMenuId(null)
+                          downloads.trigger(downloads.heapUrl(heap.id))
+                        }}
+                      />
                       <div className="my-1 h-px bg-border" />
                       <MenuItem
                         icon={<Trash2 className="h-3.5 w-3.5" />}