test(ai): prevent memory leak in provider cycle test

Use g_hash_table_new_full with g_free to ensure provider names are
properly freed when removed from the hash table. Add missing
glib.h include.

tests/unittests/test_ai_client.c

@@ -1,3 +1,4 @@
+#include "glib.h"
 #include "prof_cmocka.h"
 #include "common.h"
 #include "ai/ai_client.h"
@@ -1142,7 +1143,7 @@ test_ai_providers_find_cycles_through_many(void** state)
     ai_add_provider("alpine", "https://al.example/");
 
     /* Three providers share prefix "alp": alpha, alphabet, alpine. */
-    GHashTable* seen = g_hash_table_new(g_str_hash, g_str_equal);
+    GHashTable* seen = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, NULL);
 
     for (int i = 0; i < 3; i++) {
         auto_gchar gchar* match = ai_providers_find("alp", FALSE, NULL);