Nested tags with parent auto-apply & hierarchical search

Is your feature request related to a problem? Please describe.
I maintain natural hierarchies (i.e., franchise → character). Tagging leaf nodes requires repeatedly adding parents. Example: tagging Twilight_Sparkle should also imply My_Little_Pony and possibly Character.

Describe the solution you’d like
Parent-child (nested) tags with inheritance:

  • When applying a child tag, its parent(s) are auto-applied.

  • Searching a parent tag returns items tagged with any of its descendants.

  • Tag manager supports tree editing (drag/drop, create parent, reparent).

  • Option: store only the leaf tag in filenames but compute parents virtually to avoid filename bloat, with a toggle to materialize parents when needed.

Describe alternatives you’ve considered

  • Manual multi-tagging (time-consuming, inconsistent).

  • Encoding hierarchy in the tag string (e.g., mlp-twilight_sparkle; helps little with search semantics but is very taxing on file name size).

  • Saved searches by pattern in a separate text file (fragile and not visible on the item).

Additional context
Useful beyond media libraries: domains, projects, topics, and taxonomies. Hierarchical search plus optional virtual inheritance keeps filenames tidy while enabling powerful queries.