feat: CI orchestrator — Lambda dispatch + Fargate routing + cancel

dispatch: receives Gitea webhook, routes by runs-on label to Fargate
  tasks (go/node/docker/godot) or Lambda executor (deploy).
  Path filter evaluation, DynamoDB run tracking, cancel via StopTask.
exec: lightweight Lambda for deploy-only jobs (S3 sync, ECS update).
SAM template: API Gateway + 2 Lambdas + DynamoDB + cleanup cron.

orchestrator/dispatch/go.mod

@@ -0,0 +1,14 @@
+module tinqs.com/tinqs/ci/orchestrator/dispatch
+
+go 1.23
+
+require (
+	github.com/aws/aws-lambda-go v1.47.0
+	github.com/aws/aws-sdk-go-v2 v1.32.5
+	github.com/aws/aws-sdk-go-v2/config v1.28.0
+	github.com/aws/aws-sdk-go-v2/feature/dynamodb/attributevalue v1.15.12
+	github.com/aws/aws-sdk-go-v2/service/dynamodb v1.38.0
+	github.com/aws/aws-sdk-go-v2/service/ecs v1.52.0
+	github.com/aws/aws-sdk-go-v2/service/lambda v1.69.0
+	gopkg.in/yaml.v3 v3.0.1
+)