fix: address config injection and SIGCHLD handling

- Sanitize account names to prevent GKeyFile config injection by
  blocking special characters like #, \n, and \r.
- Ensure GLib's SIGCHLD handler is initialized before forking
  external editors to prevent zombie processes.
- Add missing error check for OMEMO random key generation.
- Replace hardcoded console tab ID with a named constant.
- Log invalid JIDs safely to prevent potential null pointer issues.

src/config/accounts.c

@@ -43,7 +43,8 @@ _sanitize_account_name(const char* const name)
     gchar* sanitized = g_strdup(name);
     gchar* p = sanitized;
     while (*p) {
-        if (*p == '[' || *p == ']' || *p == '=') {
+        // GKeyFile special characters: [ ] = # \n \r
+        if (*p == '[' || *p == ']' || *p == '=' || *p == '#' || *p == '\n' || *p == '\r') {
             *p = '_';
         }
         p++;