webui.mod enhancement

[michaelortmann]

Found by: thommey and Claude Code
Patch by: michaelortmann
Fixes:

One-line summary:

Additional description (if needed):
Issue: https://text.is/66JQ3
This PR Fixes:

1. Blocker — src/tls.c ssl_init() X509 use-after-free on error.

• Fix use after free / fingerprint logging, implemented a TODO left by (RFC) WebUI mod #1467

2. Blocker — src/tcldcc.c webui listen type works even without the webui module.

• Init webui_dcc_telnet_hostresolved() hook to null_func instead of 0
• But we dont need any fix here, because the listen type webui is only set for webui listen ports to begin with.

3. Should-fix — src/tls.c:1075-1104 HTTP-on-SSL handler hijacks every TLS listener, not just webui.

• Fixed SSL_R_HTTP_REQUEST logic to only apply to webui ports
• Response status HTTP 200 -> 400 for error msg "Error: HTTP request received on an SSL port, please try HTTPS"
• Leaking program name and version when stealth telnets is set to 1 is not a bug but a feature. nginx does the same.
• The write()/SSL_shutdown() was only suffering from a bad comment. I removed the comment, because the connection is properly closed with SO_LINGER + close(), verified with strace and tcpdump

4. killsock(): dont kill stdout, so that we keep stdout logging until the very last cycle of .die waving killsock(), it just doesnt make sense to kill stdout.
5. puts(): fix openssl error logging
6. puts(): fix memleak
7. Fix error logging for SSL_write() by doing ERR_clear_error() before that write call
8. Stop writing to sock after close notify during write and enhance logging
9. Fix fatal(): end all logging to dcc for killed sock
10. Fix memleak by calling changeover_dcc() before dcc[i].u is reused. this bug existed since at least eggdrop 1.10.1.

Test cases demonstrating functionality (if applicable):

[michaelortmann]

ready for review