fix(anilist): decode array-shaped airingSchedule/relations and isolate per-service sync errors

The 1.6.1 fix exposed a latent decoding bug: AniList returns
airingSchedule.nodes and relations.nodes as arrays, but the Go Media
struct declared Nodes as single structs. Every full-media response
failed json.Unmarshal partway through - the update path turned that
into a rejected promise which skipped the MAL and Simkl syncs and all
table updates, while page loads silently continued with partially
decoded data (the reason the old tags/genres copy workaround existed).

- Media.AiringSchedule.Nodes is now []AiringScheduleNode and
  Media.Relations is an exported []MediaRelation (previously an
  unexported field silently dropped by encoding/json); title and
  fuzzy-date sub-structs promoted to named types.
- Regenerate wailsjs models for the new shapes.
- Anime.svelte: handleSubmit and deleteEntries now wrap each service
  in its own try/catch surfaced via setApiError/ErrorModal, so one
  service failing can no longer skip the others; removed the obsolete
  tags/genres copy workaround.
- AniListUpdateEntry/AniListDeleteEntry log HTTP status and response
  body on failure for terminal diagnostics.

Bump productVersion to 1.6.2.

wails.json

@@ -12,6 +12,6 @@
   },
   "info": {
     "productName": "AniTrack",
-    "productVersion": "1.6.1"
+    "productVersion": "1.6.2"
   }
 }