Scaffold Minecraft game stubs

Add empty per-component subdirectories under src/{Analyser,Log,Parser,Pattern}/Minecraft/
with .gitkeep markers, plus MinecraftDetective stub extending the base Detective with
a TODO body. Smoke test under test/tests/Games/Minecraft/ asserts the detective is
instantiable. Introduces src/Pattern/ as a new top-level component directory.

src/Detective/Minecraft/MinecraftDetective.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace IndifferentKetchup\Codex\Detective\Minecraft;
+
+use IndifferentKetchup\Codex\Detective\Detective;
+
+class MinecraftDetective extends Detective
+{
+    // TODO: implement game-specific log type detection
+}