[WIP] Support for Single Episode Torrents

[natarelli22]

Description
As explained on #322, MediaManager currently only matches torrents that represent full seasons or season packs.
As a result, valid episode-based releases — commonly returned by indexers such as EZTV — are filtered out during scoring and never considered for download.

Initial changes to the season parsing logic allow these torrents to be discovered.
However, additional changes are required beyond season parsing to properly support single-episode imports.

This PR is intended as a work-in-progress / RFC to discuss the required changes and align on the correct approach before completing the implementation.

Things planned to do
[X] Update Web UI to better display episode-level details
[ ] Update TV show import logic to handle single episode files, instead of assuming full season files (to avoid integrity errors when episodes are missing)
[ ] Create episode file tables to store episode-level data, similar to season files
[ ] Implement fetching and downloading logic for single-episode torrents

Notes / current limitations
At the moment, the database and import logic assume one file per season per quality, which works for season packs but not for episode-based releases.

These changes are intentionally not completed yet and are part of the discussion this PR aims to start.

Request for feedback
This represents a significant change in how TV content is handled in MediaManager.
Before proceeding further, feedback from @maxdorninger on the overall direction and next steps would be greatly appreciated.

Once aligned, the remaining tasks can be implemented incrementally.

[natarelli22]

Results from the first commit (UI changes only)

On clicking on season row:

Context menu (three dots):

[maxdorninger]

Hi @natarelli22, thanks for working on this :)

Your plan looks good.

One thing I'd like to discuss is how exactly EpisodeFiles and SeasonFiles will be handled.

My idea would be that a SeasonFile will be composed of many EpisodeFiles. A SeasonFile must not contain more than 1 EpisodeFile of a specific Episode eg. S01E01. Whether an episode is imported or not would be stored in the EpisodeFile. Also the torrent associated with the episode would be stored in the EpisodeFile. But The FilePathSuffix would be stored in the SeasonFile.

This would mean when adding a torrent containing an entire season, a SeasonFile and all the EpisodeFiles will be created in the db. When adding a torrent with only one Episode, the user would have to choose to either add this one to an existing SeasonFile or create a new SeasonFile.

But as I am writing this, I realize that the SeasonFiles wouldn't be of much use then anyways since all they would do is store the FilePathSuffix and group EpisodeFiles by the FilePathSuffix. So I guess SeasonFiles could just be removed entirely since they don't really have a point when EpisodeFiles exist.