Series detection

Some resources can form sequences:
* several photos of the same place
* screenshots of long web-page
* songs of an album
* ?

When detected, such resources should be linked so a user would be able to see them together or jump from one piece of sequence to next one.

_Requires better specification_

No files, tests, or entry points are named. Start by clarifying which resource types and sequence signals are in scope, then identify the existing resource-list and navigation flows. Done means the specification defines detection, linking, and how users view or move between sequence items.

Written by the indexing model from the issue text.