feat: Update .gitignore, add Lambda layer configuration, and refactor DynamoDB handlers to use AWS SDK v3

tasker-server/terraform/layer.tf

@@ -0,0 +1,24 @@
+resource "aws_s3_bucket" "tasker_lambda_layer" {
+  bucket = "tasker-lambda-layer"
+}
+
+resource "aws_s3_object" "tasker_lambda_layer_zip" {
+  bucket = aws_s3_bucket.tasker_lambda_layer.id
+  key    = "layers/tasker-layer.zip"
+  source = "../layers/tasker-layer.zip"
+}
+
+resource "aws_lambda_layer_version" "tasker_layer" {
+  layer_name          = "tasker-layer"
+  s3_bucket           = aws_s3_object.tasker_lambda_layer_zip.bucket
+  s3_key              = aws_s3_object.tasker_lambda_layer_zip.key
+  compatible_runtimes = ["nodejs20.x"]
+
+  description = "Tasker Lambda Layer with shared dependencies"
+}
+
+resource "aws_ssm_parameter" "tasker_layer_arn" {
+  name  = "/tasker/layers/tasker-layer-arn"
+  type  = "String"
+  value = aws_lambda_layer_version.tasker_layer.arn
+}