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.

common_libs/test_framework/test_framework.nim

@@ -0,0 +1,32 @@
+## Public API for the TR integration test framework.
+## Import this module only; it re-exports all types you need.
+
+import ./server_manager
+import ./bot_compiler
+import ./battle_result
+import ./runner_process
+
+export battle_result.BattleResult
+export battle_result.BotResult
+export battle_result.RoundResult
+export battle_result.BotRoundResult
+
+proc runBattle*(botDirs: seq[string], rounds: int = 10,
+                timeout: int = 120000): BattleResult =
+  ensureServer()
+  discard compileBots(botDirs)
+  let stdout = runBattleRunner(getServerUrl(), botDirs, rounds, timeout)
+  result = parseServerOutput(stdout)
+
+when isMainModule:
+  echo "test_framework.nim — public API, not a standalone binary."
+  echo "Requires a TR server JAR. Usage from your test file:"
+  echo ""
+  echo "  import common_libs/test_framework/test_framework"
+  echo "  let r = runBattle(@[\"path/to/BotA\", \"path/to/BotB\"])"
+  echo "  echo r.winners"
+  echo ""
+  echo "Env vars forwarded to sub-modules:"
+  echo "  TR_SERVER_JAR         TR server JAR path"
+  echo "  TR_BATTLE_RUNNER      BattleRunner JAR path"
+  echo "  TR_BATTLE_RUNNER_DIR  BattleRunner class dir"