(feat) Temporal SDK client, worker mgmt, k8s deployments (#10)

## Changes
- `internal/temporal/client.go` — Robust Temporal client with retry (exp backoff), TLS, health check
- `internal/temporal/worker.go` — Worker creation, activity/workflow registration, lifecycle
- `internal/temporal/context.go` — Timeout helpers
- `k8s/worker-deployment.yaml` — 2-10 replica HPA, liveness/readiness probes, security context, pod anti-affinity
- `k8s/workflow-runner-deployment.yaml` — Singleton runner with probes
- `k8s/kustomization.yaml` — Updated resource list

Co-authored-by: poimen <[email protected]>

internal/temporal/context.go

@@ -0,0 +1,16 @@
+package temporal
+
+import (
+	"context"
+	"time"
+)
+
+// ContextWithTimeout creates a context with the given timeout.
+func ContextWithTimeout(timeout time.Duration) (context.Context, context.CancelFunc) {
+	return context.WithTimeout(context.Background(), timeout)
+}
+
+// ContextWithDefault creates a context with a default timeout of 10 seconds.
+func ContextWithDefault() (context.Context, context.CancelFunc) {
+	return context.WithTimeout(context.Background(), 10*time.Second)
+}