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/api.h

@@ -1,8 +1,9 @@
-// API module for serving embedded web content
+// API module for serving embedded web content and admin API functions
 #ifndef API_H
 #define API_H
 
 #include <libwebsockets.h>
+#include <cjson/cJSON.h>
 
 // Embedded file session data structure for managing buffer lifetime
 struct embedded_file_session_data {
@@ -14,10 +15,48 @@ struct embedded_file_session_data {
     int body_sent;
 };
 
+// Configuration change pending structure
+typedef struct pending_config_change {
+    char admin_pubkey[65];      // Who requested the change
+    char config_key[128];       // What config to change
+    char old_value[256];        // Current value
+    char new_value[256];        // Requested new value
+    time_t timestamp;           // When requested
+    char change_id[33];         // Unique ID for this change (first 32 chars of hash)
+    struct pending_config_change* next; // Linked list for concurrent changes
+} pending_config_change_t;
+
 // Handle HTTP request for embedded API files
 int handle_embedded_file_request(struct lws* wsi, const char* requested_uri);
 
 // Generate stats JSON from database queries
 char* generate_stats_json(void);
 
+// Generate human-readable stats text
+char* generate_stats_text(void);
+
+// Generate config text from database
+char* generate_config_text(void);
+
+// Send admin response with request ID correlation
+int send_admin_response(const char* sender_pubkey, const char* response_content, const char* request_id,
+                        char* error_message, size_t error_size, struct lws* wsi);
+
+// Configuration change system functions
+int parse_config_command(const char* message, char* key, char* value);
+int validate_config_change(const char* key, const char* value);
+char* store_pending_config_change(const char* admin_pubkey, const char* key,
+                                  const char* old_value, const char* new_value);
+pending_config_change_t* find_pending_change(const char* admin_pubkey, const char* change_id);
+int apply_config_change(const char* key, const char* value);
+void cleanup_expired_pending_changes(void);
+int handle_config_confirmation(const char* admin_pubkey, const char* response);
+char* generate_config_change_confirmation(const char* key, const char* old_value, const char* new_value);
+int process_config_change_request(const char* admin_pubkey, const char* message);
+
+// SQL query functions
+int validate_sql_query(const char* query, char* error_message, size_t error_size);
+char* execute_sql_query(const char* query, const char* request_id, char* error_message, size_t error_size);
+int handle_sql_query_unified(cJSON* event, const char* query, char* error_message, size_t error_size, struct lws* wsi);
+
 #endif // API_H