feat(S2-b): connect durable MQTT sync to capture workflow

FieldLogger/Services/Data/AppDatabase.cs

@@ -76,6 +76,23 @@ public sealed class AppDatabase
             .ToListAsync();
     }
 
+    public async Task<List<LoggedPoint>> GetUnsyncedPointsAsync()
+    {
+        var db = await Db;
+        return await db.Table<LoggedPoint>()
+            .Where(point => !point.Synced)
+            .OrderBy(point => point.TimestampUtc)
+            .ToListAsync();
+    }
+
+    public async Task<LoggedPoint?> GetPointBySyncIdAsync(string syncPointId)
+    {
+        var db = await Db;
+        return await db.Table<LoggedPoint>()
+            .Where(point => point.SyncPointId == syncPointId)
+            .FirstOrDefaultAsync();
+    }
+
     public async Task<int> GetPointCountAsync(int jobId)
     {
         var db = await Db;
@@ -87,4 +104,27 @@ public sealed class AppDatabase
         var db = await Db;
         await db.DeleteAsync<LoggedPoint>(pointId);
     }
+
+    public async Task UpdatePointAsync(LoggedPoint point)
+    {
+        var db = await Db;
+        await db.UpdateAsync(point);
+    }
+
+    public async Task MarkPointSyncedAsync(string syncPointId)
+    {
+        var db = await Db;
+        await db.ExecuteAsync(
+            "UPDATE points SET Synced = 1, SyncError = NULL WHERE SyncPointId = ?",
+            syncPointId);
+    }
+
+    public async Task MarkPointSyncErrorAsync(string syncPointId, string reasonCode)
+    {
+        var db = await Db;
+        await db.ExecuteAsync(
+            "UPDATE points SET Synced = 0, SyncError = ? WHERE SyncPointId = ?",
+            reasonCode,
+            syncPointId);
+    }
 }