fix: Fix functional tests infrastructure and enable connect/ping tests

Fix multiple issues preventing functional tests from running:

Stabber submodule:
- Fix XMPP stream parsing for multiple stanzas per TCP packet
- Add virtual wrapper element for Expat to handle multiple roots
- Support non-<query/> IQ payloads (ping, blocklist, etc.)
- Relax stanza matching to allow extra attributes in received

Profanity changes:
- cmd_defs.c: Increase /connect args limit from 7 to 9
- proftest.c: Add startup delay, use legacy auth, debug logging
- test_ping.c: Use wildcard IDs, regex matching, timing fixes
- functionaltests.c: Enable connect and ping test suites

Results: 9/10 tests passing

TODO:
- [ ] Fix ping_server test (disco#info response handling)
- [ ] Uncomment and fix remaining test suites (rooms, message,
      receipts, chat_session, presence, etc.)
- [ ] Remove STBBR_LOGDEBUG after stabilization
- [ ] Review timing/sleep() calls for optimization

src/command/cmd_defs.c

@@ -140,7 +140,7 @@ static const struct cmd_t command_defs[] = {
     },
 
     { CMD_PREAMBLE("/connect",
-                   parse_args, 0, 7, NULL)
+                   parse_args, 0, 9, NULL)
       CMD_MAINFUNC(cmd_connect)
       CMD_TAGS(
               CMD_TAG_CONNECTION)