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/test_basic_battle.nim

@@ -0,0 +1,30 @@
+## Integration test: OscillatorBot vs SittingDuck, 3 rounds.
+## Requires a running TR server (set TR_SERVER_JAR / TR_BATTLE_RUNNER env vars).
+
+import std/[os, unittest]
+import test_framework/test_framework
+
+const
+  oscillatorDir = currentSourcePath().parentDir.parentDir          # OscillatorBot_garage/
+  sittingDuckDir = currentSourcePath().parentDir / "bots" / "SittingDuck"
+
+suite "OscillatorBot basic battle":
+  test "beats SittingDuck in 3 rounds":
+    let r = runBattle(@[oscillatorDir, sittingDuckDir], rounds = 3)
+
+    check r.rounds.len == 3
+    check r.results.len == 2
+
+    let oscillator = block:
+      var found: BotResult
+      for b in r.results:
+        if b.name == "OscillatorBot": found = b
+      found
+    let duck = block:
+      var found: BotResult
+      for b in r.results:
+        if b.name == "SittingDuck": found = b
+      found
+
+    check oscillator.totalScore > duck.totalScore
+    check "OscillatorBot" in r.winners