extract remaining 19 modules from platform, complete stack split [ci skip]

Phase 3: all 27 platform modules now run as independent stacks.
Platform reduced to empty shell (outputs only) for backward compat
with 72 app stacks that declare dependency "platform".
Fixed technitium cross-module dashboard reference by copying file.
Woodpecker pipeline applies all 27+1 stacks in parallel via loop.
All applied with zero destroys.

stacks/redis/main.tf

@@ -0,0 +1,9 @@
+variable "tls_secret_name" { type = string }
+variable "nfs_server" { type = string }
+
+module "redis" {
+  source          = "./modules/redis"
+  tls_secret_name = var.tls_secret_name
+  nfs_server      = var.nfs_server
+  tier            = local.tiers.cluster
+}