feat: add shared integration test framework for garages (#126)

Implements:
- BattleResult type and JSON-lines parser (#127)
- TR server lifecycle manager (#128)
- Bot compiler using nim c (#129)
- runBattle() orchestrator (#130)
- Example test in OscillatorBot_garage (#131)
- Framework usage guide (#132)
- TestBattleRunner.java for external server (#133)
- BattleRunner process lifecycle (#134)

Fix: runner_process.nim was redefining TimeoutError locally; now
uses std/net.TimeoutError consistently with server_manager.nim.

OscillatorBot_garage/tests/bots/SittingDuck/src/SittingDuck.json

@@ -0,0 +1,9 @@
+{
+  "name": "SittingDuck",
+  "version": "0.1.0",
+  "authors": ["Test"],
+  "description": "Does nothing — test adversary",
+  "gameTypes": ["classic", "1v1"],
+  "platform": "Nim",
+  "programmingLang": "Nim"
+}