chat_settings: [chat] config section + live sync + fix test segfault

- New chat_setting.c/h: unified chat settings API (int/str getters)
- Config parser supports [chat] section, calls chat_setting_set per key
- chat_core exposes chat_core_set_setting / trampoline for GUI bridge
- chatgui: AudioDevice + Storage pages persist to [chat] config + live apply
- chatgui-android: ConfigProvider, NativeLib, headless handle chat settings
- MessageList: 200 msg limit, fixed saveChannelState via trampoline
- test_media_delivery_full: fix segfault at shutdown (mon() timer vs freed conns)

tools/chatgui/src/settingsdialog.cpp

@@ -88,6 +88,7 @@ SettingsDialog::SettingsDialog(const QString& configPath, DbManager* db, UtunNod
 
     // Storage page
     m_storagePage = new StorageSettingsPage(db, m_pages);
+    m_storagePage->setConfigPath(m_configPath);
     m_pages->addWidget(m_storagePage);
 
     // Network page
@@ -110,6 +111,7 @@ SettingsDialog::SettingsDialog(const QString& configPath, DbManager* db, UtunNod
     m_pages->addWidget(m_soundPage);
 
     m_audioDevicePage = new AudioDeviceSettingsPage(db, recorder, m_pages);
+    m_audioDevicePage->setConfigPath(m_configPath);
     m_pages->addWidget(m_audioDevicePage);
     rightLayout->addWidget(m_pages, 1);