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/bot_compiler.nim

@@ -0,0 +1,48 @@
+## Compiles Nim bots before battle tests.
+## config.nims in each bot dir already sets --path and --outdir, so we just
+## run `nim c src/BotName.nim` from the bot dir and let config.nims do the rest.
+
+import std/[os, osproc, streams, strformat, strutils, sequtils]
+
+proc compileBots*(botDirs: seq[string]): seq[string] =
+  ## Compiles each bot dir, returns absolute paths to compiled binaries.
+  ## Raises on first compilation failure, message includes compiler output.
+  for dir in botDirs:
+    let absDir = absolutePath(dir)
+    # Infer main source: src/<stem>.nim where stem = last path component
+    # minus optional _garage suffix (e.g. OscillatorBot_garage → OscillatorBot)
+    var stem = lastPathPart(absDir)
+    if stem.endsWith("_garage"): stem = stem[0 ..< stem.len - "_garage".len]
+
+    let srcFile = absDir / "src" / stem & ".nim"
+    if not fileExists(srcFile):
+      # Fall back: pick the first .nim in src/
+      let candidates = toSeq(walkFiles(absDir / "src" / "*.nim"))
+      if candidates.len == 0:
+        raise newException(IOError, fmt"No .nim source found in {absDir}/src/")
+      stem = splitFile(candidates[0]).name
+
+    # ponytail: startProcess+streams for timeout; execCmdEx has no timeout param
+    let p = startProcess("nim", workingDir = absDir,
+                         args = ["c", fmt"src/{stem}.nim"],
+                         options = {poUsePath, poStdErrToStdOut})
+    let exitCode = waitForExit(p, timeout = 30_000)
+    let output = p.outputStream.readAll()
+    p.close()
+    if exitCode != 0:
+      raise newException(OSError,
+        fmt"Compilation failed for {absDir}:{'\n'}{output}")
+
+    result.add absDir / "out" / stem
+
+when isMainModule:
+  let botDir = currentSourcePath().parentDir().parentDir().parentDir() /
+               "OscillatorBot_garage"
+  echo "Compiling OscillatorBot from: ", botDir
+  try:
+    let bins = compileBots(@[botDir])
+    echo "OK — binary: ", bins[0]
+    doAssert fileExists(bins[0]), "binary not found after compile"
+  except CatchableError as e:
+    echo "FAIL: ", e.msg
+    quit(1)