Prepare SILO 20261112 release candidate

Harden IAM/bucket/import/replication policy validation, enforce tag and
version authorization across read/copy/list/archive endpoints, bind SigV4
credential-scope dates and streaming trailer limits, validate HTTP SSE-KMS
contexts as strict UTF-8 JSON, add release-commit and coordinated
dependency gates, and pin silo-pkg v3.16.1, Console v2.7.1, mcli 20261112,
Go 1.27.4, and Helm chart 7.0.5.

Signed-off-by: Feng Ruohang <rh@vonng.com>

buildscripts/checkdeps.sh

@@ -7,7 +7,7 @@ _init() {
 
 	## Minimum required versions for build dependencies
 	GIT_VERSION="1.0"
-	GO_VERSION="1.27.3"
+	GO_VERSION="1.27.4"
 	OSX_VERSION="10.8"
 	KNAME=$(uname -s)
 	ARCH=$(uname -m)