chore: bump fallback version to v0.15.1

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Dicklesworthstone

pkg/version/version.go

@@ -14,7 +14,7 @@ var version string
 
 // fallback is the hardcoded version kept in sync with the latest release tag.
 // Used only when both ldflags and debug.ReadBuildInfo fail to provide a version.
-const fallback = "v0.15.0"
+const fallback = "v0.15.1"
 
 // Version is the resolved application version, populated by init().
 var Version string