fix(ui,db): harden NULL handling, fix CWE-134, optimize iterations

security(CWE-134): fix format string injections + add CI check
fix(ui): subwindow lifecycle, newwin/newpad guards, fallback timestamps
fix(db): sqlite cleanup on failures, sqlite3_close_v2
fix(xmpp): queued_messages loop, barejid leak
perf(core): g_hash_table_iter_init instead of g_hash_table_get_keys
refactor(ui): CLAMP macro in _check_subwin_width
test: XEP-0012 and XEP-0045 functional tests

Author: jabber.developer2
Closes #58, #85

src/ui/inputwin.c

@@ -144,10 +144,14 @@ void
 create_input_window(void)
 {
     /* MB_CUR_MAX is evaluated at runtime depending on the current
-     * locale, therefore we check that our own version is big enough
-     * and bail out if it isn't.
+     * locale; ensure our own compiled-in maximum is sufficient.
+     * Fail gracefully instead of aborting in production.
      */
-    assert(MB_CUR_MAX <= PROF_MB_CUR_MAX);
+    if (MB_CUR_MAX > PROF_MB_CUR_MAX) {
+        log_error("Locale MB_CUR_MAX (%zu) exceeds compiled limit (%d)", (size_t)MB_CUR_MAX, PROF_MB_CUR_MAX);
+        cons_show_error("Unsupported locale. Before running, execute in terminal: export LC_ALL=C.UTF-8");
+        return;
+    }
 #ifdef NCURSES_REENTRANT
     set_escdelay(25);
 #else
@@ -163,6 +167,10 @@ create_input_window(void)
     rl_callback_handler_install(NULL, _inp_rl_linehandler);
 
     inp_win = newpad(1, INP_WIN_MAX);
+    if (!inp_win) {
+        log_error("Failed to allocate input window pad");
+        return;
+    }
     wbkgd(inp_win, theme_attrs(THEME_INPUT_TEXT));
     keypad(inp_win, TRUE);
     wmove(inp_win, 0, 0);
@@ -238,6 +246,9 @@ inp_readline(void)
 void
 inp_win_resize(void)
 {
+    if (!inp_win) {
+        return;
+    }
     int col = getcurx(inp_win);
     int wcols = getmaxx(stdscr);
 
@@ -285,8 +296,10 @@ void
 inp_close(void)
 {
     rl_callback_handler_remove();
-    delwin(inp_win);
-    inp_win = NULL;
+    if (inp_win) {
+        delwin(inp_win);
+        inp_win = NULL;
+    }
     fclose(discard);
     discard = NULL;
 }
@@ -294,6 +307,9 @@ inp_close(void)
 char*
 inp_get_line(void)
 {
+    if (!inp_win) {
+        return NULL;
+    }
     werase(inp_win);
     wmove(inp_win, 0, 0);
     _inp_win_update_virtual();
@@ -318,6 +334,9 @@ inp_set_line(const char* const new_line)
 char*
 inp_get_password(void)
 {
+    if (!inp_win) {
+        return NULL;
+    }
     werase(inp_win);
     wmove(inp_win, 0, 0);
     _inp_win_update_virtual();