Document 1.5.15 release publishing tag

Author: eldryoth

README.md

@@ -339,6 +339,12 @@ Release tags use the same profile/OS suffixes on both registries, for example
 `v1.5.15-wolfi`, `v1.5.15-cache-wolfi`, `v1.5.15-proxy-wolfi`,
 `v1.5.15-load-balancer-wolfi`, and `v1.5.15-php-wolfi`.
 
+Release note for `1.5.15`: the signed git tag `v1.5.15` is the canonical code
+tag. The GitHub Release page is published under `v1.5.15-release` because the
+original immutable GitHub Release object for `v1.5.15` was accidentally
+deleted; GitHub reserves immutable release tag names and does not allow the
+original release page to be restored through the normal release UI/API.
+
 Manual feature selection also works:
 
 ```bash

release-notes/RELEASE_NOTES_1.5.15.md

@@ -6,6 +6,13 @@ This release adds bounded Redis `PING`, MySQL/MariaDB handshake, and
 PostgreSQL SSLRequest active health checks for load-balancer pools where TCP
 connect is not enough and an HTTP/gRPC endpoint is not available.
 
+Publishing note: the signed git tag `v1.5.15` remains the canonical code tag
+for this release. The GitHub Release page is published under
+`v1.5.15-release` because the original immutable GitHub Release object for
+`v1.5.15` was accidentally deleted; GitHub reserves immutable release tag names
+and does not allow the original release page to be restored through the normal
+release UI/API.
+
 ## What Changed
 
 - Added `protocol = "redis"` for `proxy.load_balance.health_check`.