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

tests/functionaltests/test_lastactivity.c

@@ -0,0 +1,63 @@
+/*
+ * test_lastactivity.c
+ * Functional tests for Last Activity (XEP-0012)
+ */
+#include <glib.h>
+#include "prof_cmocka.h"
+#include <stdlib.h>
+#include <string.h>
+
+#include <stabber.h>
+
+#include "proftest.h"
+
+void
+responds_to_last_activity_request(void **state)
+{
+    prof_connect();
+
+    // Send incoming last activity request
+    stbbr_send(
+        "<iq id='last1' type='get' to='stabber@localhost/profanity' from='buddy1@localhost/mobile'>"
+            "<query xmlns='jabber:iq:last'/>"
+        "</iq>"
+    );
+
+    // Verify that CProof responds with last activity info
+    // The 'seconds' attribute indicates idle time
+    assert_true(stbbr_received(
+        "<iq id='last1' type='result' to='buddy1@localhost/mobile'>"
+            "<query xmlns='jabber:iq:last' seconds='*'/>"
+        "</iq>"
+    ));
+}
+
+void
+last_activity_request_to_contact(void **state)
+{
+    prof_connect();
+
+    stbbr_send(
+        "<presence to='stabber@localhost' from='buddy1@localhost/mobile'>"
+            "<priority>10</priority>"
+            "<status>I'm here</status>"
+        "</presence>"
+    );
+    assert_true(prof_output_exact("Buddy1 (mobile) is online, \"I'm here\""));
+
+    // Register response for last activity query
+    stbbr_for_query("jabber:iq:last",
+        "<iq id='*' type='result' from='buddy1@localhost/mobile' to='stabber@localhost/profanity'>"
+            "<query xmlns='jabber:iq:last' seconds='120'/>"
+        "</iq>"
+    );
+
+    prof_input("/lastactivity get buddy1@localhost/mobile");
+
+    // Verify the request was sent
+    assert_true(stbbr_received(
+        "<iq id='*' to='buddy1@localhost/mobile' type='get'>"
+            "<query xmlns='jabber:iq:last'/>"
+        "</iq>"
+    ));
+}