v0.7.25 - Implement SQL Query Admin API

- Move non-NIP-17 admin functions from dm_admin.c to api.c for better architecture
- Add NIP-44 encryption to send_admin_response() for secure admin responses
- Implement SQL query validation and execution with safety limits
- Add unified SQL query handler for admin API
- Fix buffer size for encrypted content to handle larger responses
- Update function declarations and includes across files
- Successfully test frontend query execution through web interface

src/subscriptions.c

@@ -123,7 +123,7 @@ void free_subscription_filter(subscription_filter_t* filter) {
 }
 
 // Validate subscription ID format and length
-static int validate_subscription_id(const char* sub_id) {
+int validate_subscription_id(const char* sub_id) {
     if (!sub_id) {
         return 0; // NULL pointer
     }
@@ -133,11 +133,11 @@ static int validate_subscription_id(const char* sub_id) {
         return 0; // Empty or too long
     }
 
-    // Check for valid characters (alphanumeric, underscore, hyphen, colon)
+    // Check for valid characters (alphanumeric, underscore, hyphen, colon, comma)
     for (size_t i = 0; i < len; i++) {
         char c = sub_id[i];
         if (!((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') ||
-              (c >= '0' && c <= '9') || c == '_' || c == '-' || c == ':')) {
+              (c >= '0' && c <= '9') || c == '_' || c == '-' || c == ':' || c == ',')) {
             return 0; // Invalid character
         }
     }