fix: merge sessions from all types (BackupJob, FileBackupJob, AgentBackupJob, unfiltered)

- fetch_sessions now queries 5 URL variants and merges results
  by unique session id (no duplicates)
- First query: unfiltered with 3x limit (gets recent sessions of all types)
- Then: sessionType=BackupJob, FileBackupJob, AgentBackupJob
- Ensures all backup job types appear in dashboard

veeam_client.py

@@ -241,16 +241,25 @@ class VeeamClient:
 
     async def fetch_sessions(self, limit: int = 50) -> list[dict]:
         if self._is_v12():
+            seen: set[str] = set()
+            all_sessions: list[dict] = []
             for path in (
-                f"/api/v1/sessions?limit={limit}",
-                f"/api/v1/sessions?limit={limit}&sessionType=BackupJobs",
-                f"/api/v1/sessions?limit={limit}&sessionType=BackupJobs&typeFilter=Backup",
+                f"/api/v1/sessions?limit={limit * 3}",
+                f"/api/v1/sessions?limit={limit}&sessionType=BackupJob",
+                f"/api/v1/sessions?limit={limit}&sessionType=BackupJob&typeFilter=Backup",
+                f"/api/v1/sessions?limit={limit}&sessionType=FileBackupJob",
+                f"/api/v1/sessions?limit={limit}&sessionType=AgentBackupJob",
             ):
                 try:
-                    return await self._fetch_json_list(path)
+                    items = await self._fetch_json_list(path)
+                    for s in items:
+                        sid = s.get("id") or s.get("Id") or ""
+                        if sid and sid not in seen:
+                            seen.add(sid)
+                            all_sessions.append(s)
                 except Exception:
                     continue
-            return []
+            return all_sessions
         return await self._fetch_legacy_sessions(limit)
 
     async def fetch_repositories(self) -> list[dict]: