feat: major restructuring in migration to terragrunt

- migrate from individual terraform files to config-driven terragrunt module structure
- add vault_cluster module with config discovery system
- replace individual .tf files with centralized config.hcl
- restructure auth and secret backends as configurable modules
- move auth roles and secret backends to yaml-based configuration
- convert policies from .hcl to .yaml format, add rules/auth definition
- add pre-commit hooks for yaml formatting and file cleanup
- add terragrunt cache to gitignore
- update makefile with terragrunt commands and format target

modules/vault_cluster/modules/transit_secret_backend/main.tf

@@ -0,0 +1,7 @@
+resource "vault_mount" "transit" {
+  path                      = var.path
+  type                      = "transit"
+  description               = var.description
+  default_lease_ttl_seconds = var.default_lease_ttl_seconds
+  max_lease_ttl_seconds     = var.max_lease_ttl_seconds
+}

modules/vault_cluster/modules/transit_secret_backend/variables.tf

@@ -0,0 +1,22 @@
+variable "path" {
+  description = "Mount path of the transit secrets engine"
+  type        = string
+}
+
+variable "description" {
+  description = "Human-friendly description of the mount"
+  type        = string
+  default     = null
+}
+
+variable "default_lease_ttl_seconds" {
+  description = "Default lease TTL in seconds"
+  type        = number
+  default     = 3600
+}
+
+variable "max_lease_ttl_seconds" {
+  description = "Maximum lease TTL in seconds"
+  type        = number
+  default     = 86400
+}