Filter patterns (subscription subFilter, policy-group Filter, message
MsgFilter) accept arbitrary user input while the tested text (remarks
from subscriptions, log lines) is attacker-influenced. Regex.IsMatch
without timeout hangs on evil patterns like (a+)+$ - a malicious
subscription can freeze the UI/log pipeline on every update.
Add Utils.IsRegexMatch with a 2s timeout; fail open (match) with a log
so no node or message is silently dropped. Apply to all four call
sites.
Co-authored-by: sdhfsl <sdhfsl@users.noreply.github.com>
