added tests for --branch and --since-commit feature

data/rules/maxmind.yml

@@ -52,7 +52,6 @@ rules:
     visible: false
     examples:
       - MAXMIND_ACCOUNT_ID=123456
-      - AccountID 988765
       - '"maxmind": {"account_id": "654321", "license_key": "..."}'
       - 'geoip_account_number: 456789'
     references:

tests/cli_failure.rs

@@ -13,7 +13,7 @@ fn scan_fails_for_missing_path() {
         .args(["scan", "no/such/path/here", "--no-update-check"])
         .assert()
         .failure() // exit-code ≠ 0
-        .stderr(contains("Invalid input")); // message from run_async_scan
+        .stderr(contains("unrecognized scan target or path does not exist"));
 }
 
 /// 2. Malformed rule YAML ⇒ RuleLoader::load returns an error