chore: enable tflint-ruleset-azurerm rules

.tflint.hcl

@@ -1,13 +1,39 @@
+plugin "azurerm" {
+  enabled = true
+  version = "0.28.0"
+  source  = "github.com/terraform-linters/tflint-ruleset-azurerm"
+}
+
+# Azure resource validation — fail CI on invalid azurerm config values we just
+# migrated to in the 3.x → 4.x cutover. Names that did not exist in
+# tflint-ruleset-azurerm v0.28.0 (e.g. *_invalid_account_tier,
+# *_invalid_account_replication_type) are tracked as TODO so we can revisit
+# when the upstream ruleset adds them.
+rule "azurerm_storage_account_invalid_access_tier" {
+  enabled = true
+}
+rule "azurerm_storage_account_invalid_account_kind" {
+  enabled = true
+}
+rule "azurerm_resource_missing_tags" {
+  enabled = false # TODO: flip to true after fleet-wide tag policy is defined
+}
+
+# Standard terraform plugin rules
 plugin "terraform" {
   enabled = true
   preset  = "recommended"
 }
 
-plugin "azurerm" {
+rule "terraform_required_version" {
   enabled = true
-  version = "0.28.0"
-  source  = "github.com/terraform-linters/tflint-ruleset-azurerm"
 }
-
-# Azurerm rules — installed but NOT enforced yet. Enablement deferred to Phase 4.
-# Individual rule enables go here after Phase 1 4.x migration is complete.
+rule "terraform_required_providers" {
+  enabled = true
+}
+rule "terraform_documented_variables" {
+  enabled = false # TODO: too noisy for module surfaces; revisit per repo
+}
+rule "terraform_documented_outputs" {
+  enabled = false # TODO: too noisy; revisit per repo
+}