fix: keep the monitored state when a season is partially downloaded

[Raffa2001]

Fixes #31.

The problem

Any TV request whose season is partially downloaded — the normal state of a
currently airing show — is shown as Missing (Unmonitored) on the Requests tab,
even when every episode is monitored in Sonarr.

ServarrProgressService.cs decides the label with this chain (lines ~330–348):

if (allUnreleased && !anyFile)      return ... // Unreleased
if (allHaveFiles && allMonitored)   return ... // Downloaded (Monitored)
if (allHaveFiles)                   return ... // Downloaded (Unmonitored)
if (!anyFile && anyMonitored)       return ... // Missing (Monitored)
return BuildLibraryProgress(false, false, ...); // Missing (Unmonitored)

There are branches for nothing downloaded and for everything downloaded, but
none for some episodes downloaded:

• allHaveFiles is false → branches 2 and 3 are skipped
• !anyFile is false → branch 4 is skipped, even when every episode is
  monitored

So it reaches the final return, which hardcodes monitored: false. The
label's second half is then simply untrue.

This is not about season scoping — FilterEpisodesBySeasons works correctly.
Verified below: restricting to the requested season changes the episode count
but not the outcome.

The change

-        return BuildLibraryProgress(false, false, false, 0, seriesOpenUrl);
+        return BuildLibraryProgress(false, anyMonitored, false, 0, seriesOpenUrl);

BuildLibraryProgress(hasFile: false, monitored: true, …) already renders
Missing (Monitored), so no new state is introduced and no other branch changes
behaviour — the earlier !anyFile && anyMonitored return covers the "nothing
downloaded yet" case identically.

Verified against

Request	Episodes in requested season	With a file	Monitored	Before	After
Tomb Raider King — s1	12	4	10	Missing (Unmonitored)	Missing (Monitored)
That Time I Got Reincarnated as a Slime — s4	24	4	10	Missing (Unmonitored)	Missing (Monitored)

Numbers taken from GET /api/v3/episode?seriesId=N. In the second case the
season filter is demonstrably active — the requested season yields 24 episodes
where the whole series has 96 — and the label was unchanged, which is what rules
scoping out as the cause.

Environment: SeerrFin 1.6.6.0 · Jellyfin 10.11.11 · Sonarr 4.0.19.2979 ·
Jellyseerr 3.4.1.

Builds clean against JellyfinVersion=10.11.11 on .NET 9 — 0 warnings, 0 errors.

Possible follow-up (not in this PR)

A partially downloaded season could deserve its own state rather than sharing
Missing: the progress bar currently reads 0% while totalSize is already
known for the episodes that do have files, so it could show real progress.

Also worth knowing: Sonarr's series-level statistics.episodeFileCount counts
only monitored episodes — it reports 4/4 for the first case above while the
episode list reports 4 of 12. If that field is used anywhere the two numbers
will disagree in exactly this scenario.