feat(ci,iac): Consolidate Forgejo CI workflows and add Talos Terraform IaC

Consolidate three separate Forgejo Actions (argocd-sync, security-scan, validate-k8s) into single cluster-ci workflow for cleaner CI/CD pipeline with proper job sequencing and reduced auth overhead.

Add Terraform configuration for Talos cluster machine configs:
- Provider setup for Talos
- Centralized variables for CP and worker configs
- Template-based config generation for controlplane.yaml and worker-*.yaml
- Sensitive data separated in terraform.tfvars (gitignored)
- Local state tracking for infrastructure

terraform/.gitignore

@@ -0,0 +1,15 @@
+# Terraform state
+*.tfstate
+*.tfstate.*
+.terraform/
+.terraform.lock.hcl
+
+# Variables with secrets
+terraform.tfvars
+*.auto.tfvars
+
+# IDE
+.vscode/
+*.swp
+*.swo
+*~