fix(logic): chat length limit logic

[Rushaway]

PR Description

Summary

• Fixes chat overflow exceptions caused by oversized ConnectAnnounce messages.
• Safely truncates output to chat limits.
• Adds short user-facing notices when a join message is truncated or skipped.

What changed

• Remove format-token neutralization
• Updated warning texts with concise call-to-action (sm_joinmsg).
• Refactored announce truncation logic to be explicit and readable:
  • truncate base announcement if needed
  • append join message only when space is available
  • truncate appended join message when necessary

Why

• Prevents runtime SayText2 overflow errors.
• Keeps behavior predictable for long historical/custom messages.

User impact

• No more error DLL_MessageEnd: Refusing to send user message SayText2 of 256 bytes to client, user message size limit is 255 bytes
• Players are informed when their custom message is truncated/skipped and how to fix it.

Testing

• Manually validated long join-message scenarios: append, truncate, and skip paths.

[Copilot]

Pull request overview

This PR addresses Source engine chat overflow (SayText2) issues in ConnectAnnounce by sanitizing stored/per-user join messages and enforcing a safe length cap when building the final announcement string.

Changes:

• Added SanitizeClientJoinMessage() and applied it when loading join messages from local KeyValues and SQL (with a lazy “sanitize then persist” migration).
• Introduced explicit truncation/skip logic to keep the final SayText2 output under a fixed length budget, with user-facing notices.
• Bumped plugin version to 2.5.6 and added a MAX_SAYTEXT2_LENGTH constant.

Comments suppressed due to low confidence (1)

addons/sourcemod/scripting/ConnectAnnounce.sp:1413

• CPrintToChat* treats the first string parameter as a format string. Since sFinalMessage includes user-controlled content (e.g., {NAME} from GetClientName and potentially join messages), any % sequences can be interpreted as format specifiers and trigger runtime errors or be abused to spam errors. To avoid format-string injection, pass the message as a data parameter (e.g., use a constant format like %s and provide sFinalMessage as an argument), and/or ensure all % characters in inserted user content are escaped.

			Format(sFinalMessage, sizeof(sFinalMessage), "%s %s", sFinalMessage, sSafeJoinMessage);
		}
	}

	if (sendToAll)
		CPrintToChatAll(sFinalMessage);
	else
		CPrintToChat(client, sFinalMessage);