fix(buildscripts): fail rebrand verification when ripgrep is missing

Check the existing ripgrep prerequisite before searches whose conditional
status handling would otherwise hide command-not-found failures. Preserve
untracked-file coverage and verification from a source archive without Git.

Addresses the missing-tool finding recorded in commit
4fb3a7fa3b175727db987f3ba2523c84f74d4168 without its scan-scope changes.

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

buildscripts/verify-rebrand.sh

@@ -11,6 +11,8 @@ fail() {
 	exit 1
 }
 
+command -v rg >/dev/null 2>&1 || fail "ripgrep (rg) is required for rebrand verification"
+
 require_file() {
 	[ -f "$1" ] || fail "missing required file: $1"
 }