chore: remove issue ID references from comments and changelogs

Strip (bd-xxx), (gt-xxx) suffixes from code comments and changelog
entries. The descriptions remain meaningful without the ephemeral
issue IDs.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/rpc/server_labels_deps_comments.go

@@ -32,7 +32,7 @@ func (s *Server) handleDepAdd(req *Request) Response {
 		}
 	}
 
-	// Check for child→parent dependency anti-pattern (bd-nim5)
+	// Check for child->parent dependency anti-pattern
 	// This creates a deadlock: child can't start (parent open), parent can't close (children not done)
 	if isChildOf(depArgs.FromID, depArgs.ToID) {
 		return Response{