Fix #18: Exception leak remediation across 87 PHP files

- Replaced all client-facing $e->getMessage() with generic error messages
- Added error_log() with filename prefix to all catch blocks
- Covered jsonError(), echo, and json_encode() response patterns
- Also fixed 2 remaining display_errors=1 and add_invoice.php leak
- Script-assisted fix for 75 files, manual fix for 12 remaining edge cases

backend/Admin/v2/analytics/driver_ranking.php

@@ -38,6 +38,7 @@ try {
     ]);
 } catch (Exception $e) {
     http_response_code(500);
-    echo json_encode(['status' => 'error', 'message' => $e->getMessage()]);
+    error_log("[driver_ranking.php] " . $e->getMessage());
+    echo json_encode(['status' => 'error', 'message' => 'An internal error occurred']);
 }
 ?>

backend/Admin/v2/analytics/growth.php

@@ -53,6 +53,7 @@ try {
     ]);
 } catch (Exception $e) {
     http_response_code(500);
-    echo json_encode(['status' => 'error', 'message' => $e->getMessage()]);
+    error_log("[growth.php] " . $e->getMessage());
+    echo json_encode(['status' => 'error', 'message' => 'An internal error occurred']);
 }
 ?>

backend/Admin/v2/analytics/revenue.php

@@ -47,6 +47,7 @@ try {
     ]);
 } catch (Exception $e) {
     http_response_code(500);
-    echo json_encode(['status' => 'error', 'message' => $e->getMessage()]);
+    error_log("[revenue.php] " . $e->getMessage());
+    echo json_encode(['status' => 'error', 'message' => 'An internal error occurred']);
 }
 ?>