Add ProjectZomboidClientActionLog (ClientActionLog.txt)

Strict 5-field bracketed format. Parser captures only the timestamp;
analysers that want steamid/action/player/coords/param decompose the
Line text via ClientActionPattern::FIELDS. Detectors: filename match
plus content signature on the IS{Enter,Exit}Vehicle / ISWalkToTimedAction
action tokens.

src/Pattern/ProjectZomboid/ClientActionPattern.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace IndifferentKetchup\Codex\Pattern\ProjectZomboid;
+
+/**
+ * Regex constants for the Project Zomboid ClientActionLog.txt format.
+ *
+ * Strict 5-field bracketed structure:
+ *   [time] [steamid][action][player][x,y,z][param].
+ *
+ * LINE captures, in order:
+ *   1. time (DD-MM-YY HH:MM:SS.mmm)
+ *
+ * The remaining bracketed fields are extractable via FIELDS for analysers.
+ */
+class ClientActionPattern
+{
+    public const string LINE = '/^\[(\d{2}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\.\d{3})\] \[\d{17}\]\[[^\]]+\]\[[^\]]+\]\[\d+,\d+,\d+\]\[[^\]]+\]\.$/';
+
+    public const string FIELDS = '/^\[\d{2}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\.\d{3}\] \[(?<steamid>\d{17})\]\[(?<action>[^\]]+)\]\[(?<player>[^\]]+)\]\[(?<x>\d+),(?<y>\d+),(?<z>\d+)\]\[(?<param>[^\]]+)\]\.$/';
+}