fix(identity): support negative integers in isNumeric for Telegram group IDs

pkg/identity/identity.go

@@ -94,13 +94,18 @@ func MatchAllowed(sender bus.SenderInfo, allowed string) bool {
 	return false
 }
 
-// isNumeric returns true if s consists entirely of digits.
+// isNumeric returns true if s consists entirely of digits, allowing for an optional leading minus sign
+// (required for Telegram group/channel IDs like -1001234567890).
 func isNumeric(s string) bool {
 	if s == "" {
 		return false
 	}
-	for _, r := range s {
-		if r < '0' || r > '9' {
+	start := 0
+	if s[0] == '-' && len(s) > 1 {
+		start = 1
+	}
+	for i := start; i < len(s); i++ {
+		if s[i] < '0' || s[i] > '9' {
 			return false
 		}
 	}

pkg/identity/identity_test.go

@@ -97,6 +97,15 @@ func TestMatchAllowed(t *testing.T) {
 			allowed: "654321",
 			want:    false,
 		},
+		{
+			name: "negative numeric ID matches PlatformID",
+			sender: bus.SenderInfo{
+				Platform:   "telegram",
+				PlatformID: "-1001234567890",
+			},
+			allowed: "-1001234567890",
+			want:    true,
+		},
 		// Username matching
 		{
 			name:    "@username matches Username",
@@ -238,6 +247,9 @@ func TestIsNumeric(t *testing.T) {
 		{"abc", false},
 		{"12a34", false},
 		{"telegram", false},
+		{"-1001234567890", true},
+		{"-", false},
+		{"-12a34", false},
 	}
 
 	for _, tt := range tests {