docs(test_framework): add comprehensive integration test guide and fix runner blocking issue

- Document exception handling, zero-value BotResult trap, shared adversary bots
- Add offline parsing example using parseServerOutput
- Skip tests gracefully when JARs missing (guard before suite blocks)
- Fix blocking readLine in runner_process.nim: poll with 50ms sleep + atEnd check
  (was preventing timeout enforcement, now blocks correctly during battle)
- Add test task to QBot.nimble and config.nims setup docs to AGENTS.md
- Add debug logging to TestBattleRunner for bot identity tracking

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

common_libs/test_framework/adversaries/SittingDuck/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"
+}