feat(multi-instance): dcy-009 BAT-013 — RabbitMQ 다중 인스턴스 토폴로지 (REQ-048~051)

dcy-009(다중 인스턴스 RabbitMQ 토폴로지) 전체 SDLC: draft-req → confirm-req →
draft-batch(BAT-013) → run-batch-delivery → confirm-req-implemented.

- REQ-048 (Configuration): DaemonInstanceConfig.from_toml + DaemonConfig.from_config
  (env 병합, portfolio_hub_token 주입) + 데몬 --config 필수 argparse + .gitignore 인스턴스
  TOML + config/instance.example.toml
- REQ-049 (Interface): topology 동적 큐명 빌더 intent/snapshot/control_queue(instance_key)
  — default=리터럴 큐명(하위호환), named=`{base}.{instance_key}` + daemon per-instance 구독
- REQ-050 (Integration): trex.direct(topic)/trex.broadcast(fanout) exchange +
  declare_topology(instance_key) per-instance binding + control dual binding + direct_routing_key
- REQ-051 (Documentation): interface-contract/runtime-flows/project-structure 정합

하위호환: instance_key="default" → 기존 리터럴 큐명·RPC 경로 무회귀(FR-5).
split-brain 방지(NFR-3): 인스턴스 전용 큐. 민감값(NFR-4): TOML + gitignore.

검증: 신규 9 단위 + RabbitMQ 라우팅 2, 단위 271 passed,
인프라 게이트 301 passed(directed 격리 S-2 + broadcast dual S-3 + default 무회귀 S-4),
ruff clean. REQ-048~051 Implemented, BAT-013 release-candidate.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

config/instance.example.toml

@@ -0,0 +1,12 @@
+# trex-core per-instance config (BAT-013 / REQ-048).
+# Copy to e.g. config/inst-1.toml and pass with: trex-core-daemon --config config/inst-1.toml
+# Real per-instance files are gitignored (they hold the portfolio-hub token).
+
+# Instance identifier. Drives queue names:
+#   default        -> trex.intent.req / trex.snapshot.req / trex.control.req (legacy literal)
+#   <other>        -> trex.intent.req.<instance_key> etc + trex.direct routing key {instance_key}.{channel}
+instance_key = "default"
+
+# portfolio-hub auth token (kept out of .env). Injected into PortfolioHubConfig.token
+# when TREX_PORTFOLIO_HUB_BASE_URL is set in the environment.
+portfolio_hub_token = ""