feat: share heaps and folders with other users, fix auth and vision pipeline

Sharing:
- New HeapShare and FolderShare models with read/write permissions
- Sharing API router (CRUD for heap and folder shares)
- Heap endpoints accept shared access (photo_ids, add/remove with write)
- Photo list drops user_id filter in shared context, adds owner_username
- Media serving (thumb/original/proxy) falls back to share check on 404
- ShareDialog component for managing shares from kebab menus
- HeapsPanel shows "Shared with me" section for shared heaps
- LeftSidebar shows "Shared with me" section for shared folders
- Owner badge on PhotoThumbnail for photos from other users

Auth:
- Access token default bumped to 1 year, refresh to 10 years
- Refresh token persisted in localStorage (survives page reload)
- Timer-based refresh replaced with 401 axios interceptor

Vision pipeline fixes:
- Bootstrap sets Redis ready key even on partial export failure
- Export functions run conditionally (only for actually missing models)
- _load_thumb handles multi-user path (/data/thumbs/{user_id}/{photo_id}/)
- can_access_photo_via_share uses single subquery instead of N+1 loop

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

frontend/src/components/layout/LeftSidebar.tsx

@@ -44,6 +44,8 @@ import {
 import { registerUndoable } from '../../store/undoStore'
 import type { Photo } from '../../types/photo'
 import { DeleteFolderDialog } from '../dialogs/DeleteFolderDialog'
+import { ShareDialog } from '../sharing/ShareDialog'
+import { useSharedFoldersQuery } from '../../hooks/useSharingQueries'
 import { useAuth } from '../../contexts/AuthContext'
 
 interface TreeItem {
@@ -111,6 +113,11 @@ export function LeftSidebar({ onCollapse }: LeftSidebarProps) {
     name: string
     photoCount?: number
   } | null>(null)
+  const [sharingFolder, setSharingFolder] = useState<{
+    id: string
+    name: string
+  } | null>(null)
+  const { data: sharedFolders = [] } = useSharedFoldersQuery()
 
   // Bulk discard mutation for the drag-onto-Discarded interaction.
   const discardDropMutation = useMutation({
@@ -703,6 +710,14 @@ export function LeftSidebar({ onCollapse }: LeftSidebarProps) {
                           })
                         }}
                       />
+                      <FolderMenuItem
+                        icon={<Users className="h-3.5 w-3.5" />}
+                        label="Share…"
+                        onClick={() => {
+                          setOpenMenuId(null)
+                          setSharingFolder({ id: folderId, name: item.label })
+                        }}
+                      />
                       <div className="my-1 h-px bg-border" />
                       <FolderMenuItem
                         icon={<Trash2 className="h-3.5 w-3.5" />}
@@ -803,6 +818,53 @@ export function LeftSidebar({ onCollapse }: LeftSidebarProps) {
       {/* Tree View */}
       <div className="flex-1 overflow-y-auto pb-2">
         {libraryTree.map((item) => renderTreeItem(item))}
+
+        {/* Shared with me — folders shared by other users */}
+        {sharedFolders.length > 0 && (
+          <div className="mt-1">
+            <div className="px-3 py-1 text-[10px] font-semibold uppercase tracking-[0.14em] text-text-muted">
+              Shared with me
+            </div>
+            {sharedFolders.map((sf) => {
+              const isSelected = currentSection === `folder-${sf.id}`
+              return (
+                <div
+                  key={sf.id}
+                  className={clsx(
+                    'flex h-[24px] cursor-pointer items-center gap-1 rounded px-2 text-[12px] leading-none',
+                    isSelected ? 'bg-primary/20 text-primary' : 'text-text hover:bg-surface-2',
+                  )}
+                  style={{ paddingLeft: '20px' }}
+                  onClick={() =>
+                    navigateToSection(`folder-${sf.id}`, { folderId: sf.id })
+                  }
+                >
+                  <Users
+                    className={clsx(
+                      'h-3.5 w-3.5 flex-shrink-0',
+                      isSelected ? 'text-primary' : 'text-text-muted'
+                    )}
+                  />
+                  <span className="truncate" title={sf.name}>
+                    {sf.name}
+                  </span>
+                  <span className="ml-0.5 truncate text-[10px] text-text-faint">
+                    {sf.owner_username}
+                  </span>
+                  <span className="ml-auto rounded bg-surface-offset px-1 text-[9px] uppercase text-text-faint">
+                    {sf.permission}
+                  </span>
+                  {sf.photo_count > 0 && (
+                    <span className="flex h-4 min-w-[20px] flex-shrink-0 items-center justify-center rounded bg-surface-offset px-1 text-[10px] tabular-nums text-text-muted">
+                      {sf.photo_count}
+                    </span>
+                  )}
+                </div>
+              )
+            })}
+          </div>
+        )}
+
         <HeapsPanel />
       </div>
 
@@ -853,6 +915,13 @@ export function LeftSidebar({ onCollapse }: LeftSidebarProps) {
           }
         }}
       />
+      <ShareDialog
+        isOpen={!!sharingFolder}
+        type="folder"
+        targetId={sharingFolder?.id ?? ''}
+        targetName={sharingFolder?.name ?? ''}
+        onClose={() => setSharingFolder(null)}
+      />
     </div>
   )
 }