fix: SonarrSync now deletes episodes per-series to prevent incomplete cache

Fixes #5306 - Sonarr items are not showing as available

Root cause:
SonarrSync was deleting ALL episodes from SonarrEpisodeCache at the start of
the job, then re-adding them one series at a time. If the job failed
partway through (API timeout, network issue, etc.), the cache would be
left incomplete with only some series' episodes. This caused shows to be
incorrectly marked as unavailable.

Changes:
- Moved DELETE FROM SonarrEpisodeCache inside the series loop
- Now deletes episodes per series (by TvDbId) before adding new ones
- If job fails mid-way, cache for already-processed series remains intact

This ensures that partial failures don't result in completely empty cache.

Author: Jamie

src/Ombi.Schedule/Jobs/Sonarr/SonarrSync.cs

@@ -92,13 +92,6 @@ await strat.ExecuteAsync(async () =>
                     await _ctx.SonarrCache.AddRangeAsync(sonarrCacheToSave);
                     await _ctx.SaveChangesAsync();
                     sonarrCacheToSave.Clear();
-                    strat = _ctx.Database.CreateExecutionStrategy();
-                    await strat.ExecuteAsync(async () =>
-                    {
-                        using var tran = await _ctx.Database.BeginTransactionAsync();
-                        await _ctx.Database.ExecuteSqlRawAsync("DELETE FROM SonarrEpisodeCache");
-                        await tran.CommitAsync();
-                    });
 
                     foreach (var s in ids)
                     {
@@ -111,6 +104,15 @@ await strat.ExecuteAsync(async () =>
                         var episodes = await _api.GetEpisodes(s.Id, settings.ApiKey, settings.FullUri);
                         var monitoredEpisodes = episodes.Where(x => x.monitored || x.hasFile);
 
+                        // Delete existing episodes for this series before adding new ones
+                        strat = _ctx.Database.CreateExecutionStrategy();
+                        await strat.ExecuteAsync(async () =>
+                        {
+                            using var tran = await _ctx.Database.BeginTransactionAsync();
+                            await _ctx.Database.ExecuteSqlRawAsync("DELETE FROM SonarrEpisodeCache WHERE TvDbId = {0}", s.TvDbId);
+                            await tran.CommitAsync();
+                        });
+
                         //var allExistingEpisodes = await _ctx.SonarrEpisodeCache.Where(x => x.TvDbId == s.tvdbId).ToListAsync();
                         // Add to DB
                         _log.LogDebug("We have the episodes, adding to db transaction");