fix: add 'user' and 'guest' to placeholder name blocklist to prevent false merges (CM-1137)

Signed-off-by: Yeganathan S <63534555+skwowet@users.noreply.github.com>

Author: skwowet

services/apps/merge_suggestions_worker/src/utils.ts

@@ -48,10 +48,10 @@ export function stripProtocol(value: string) {
   return value.replace(/^https?:\/\//, '')
 }
 
-const OS_RESERVED_NAMES = new Set(['unknown', 'root', 'ubuntu', 'admin'])
+// Generic git user.name placeholders and OS account names that are never a real human
+// identity — shared across unrelated machines and meaningless as a merge signal.
+const OS_RESERVED_NAMES = new Set(['unknown', 'root', 'ubuntu', 'admin', 'user', 'guest'])
 
-// OS-level account names that are never a real human identity — shared across
-// thousands of unrelated machines and meaningless as a merge signal.
 export function isOsReservedName(name: string): boolean {
   return OS_RESERVED_NAMES.has(name.trim().toLowerCase())
 }