feat(config): config 디렉터리 기반 설정 관리 (--config-path/--env-file, trex-orb-v1 정합, BAT-026)

REQ-048/010 change-req. `--config` 를 이름으로 해석 + `--config-path <dir>`
(기본 ./config) + resolve_config_toml(슬래시 포함 값은 하위호환 명시 경로).
`.env` 를 config-dir 결정적 해석(--env-file 우선, 없으면 <config_dir>/.env,
CWD 무관) + config/.env.example + .gitignore config/* 허용목록. 운영자 CLI 도
--config-path/--env-file 동일 적용. from_env() legacy 루트 .env 폴백 유지로
완전 하위호환.

단위 23 + 전체 375 passed, ruff clean, 라이브 스모크(name·path 동일).
REQ-048/010 → Implemented.

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

config/.env.example

@@ -0,0 +1,57 @@
+# trex-core shared infrastructure + secrets (12-factor, REQ-010 CHG-20260609-01).
+#
+# These are SHARED across all per-instance TOML configs in this directory (same
+# DB / broker / portfolio-hub / RabbitMQ), so they live here instead of the
+# per-instance TOML.
+#
+# Resolution (trex_core.runtime.config):
+#   config_dir = --config-path  (default ./config)
+#   --env-file <path>   wins, else  <config_dir>/.env
+#   (standalone reads with no config fall back to legacy CWD-relative .env)
+#   Real exported environment variables ALWAYS take precedence over this file.
+#   Use --config-path <abs-dir> to stay CWD-independent when launching elsewhere.
+#
+# Copy this template to `.env` in the same config dir and fill in:
+#   cp config/.env.example config/.env
+
+# --- Core (required) ---
+# psycopg DSN for the PostgreSQL single-writer store.
+TREX_POSTGRESQL_DSN=dbname=trex_core host=/var/run/postgresql
+
+# --- Daemon (optional, defaults shown) ---
+TREX_TOTAL_SLOTS=10
+TREX_EXECUTION_INTERVAL_SEC=1.0
+
+# --- Broker selection (REQ-011/012/013) ---
+# 'paper' (deterministic test double, default) | 'kis' (real KIS Open API)
+TREX_BROKER=paper
+
+# --- Paper broker tuning (only when TREX_BROKER=paper; for e2e scenarios) ---
+# TREX_PAPER_FILL_AFTER_POLLS=0
+# TREX_PAPER_QTY_PER_POLL=
+# TREX_PAPER_REJECT_SYMBOLS=
+
+# --- KIS broker (only when TREX_BROKER=kis) ---
+# 모의투자(sandbox): https://openapivts.koreainvestment.com:29443
+# 실계좌(live): https://openapi.koreainvestment.com:9443  (requires TREX_KIS_ALLOW_LIVE=true)
+TREX_KIS_BROKER_BASE_URL=https://openapivts.koreainvestment.com:29443
+TREX_KIS_BROKER_TIMEOUT=5
+TREX_KIS_BROKER_APP_KEY=
+TREX_KIS_BROKER_APP_SECRET=
+TREX_KIS_BROKER_ACCOUNT_REF=12345678-01
+TREX_KIS_ALLOW_LIVE=false
+TREX_KIS_REDIS_URL=
+
+# --- portfolio-hub ledger (REQ-017/018/019, BAT-006) ---
+# portfolio_hub_token is per-instance and lives in the instance TOML, not here.
+TREX_PORTFOLIO_HUB_BASE_URL=
+TREX_PORTFOLIO_HUB_TIMEOUT=5
+TREX_LEDGER_INTERVAL_SEC=1.0
+
+# --- Snapshot scheduler (REQ-030, BAT-008) ---
+TREX_SNAPSHOT_SCHEDULE_KST=07:30
+TREX_SNAPSHOT_TICK_SEC=60
+
+# --- RabbitMQ transport (REQ-022, BAT-007) ---
+TREX_RABBITMQ_URL=
+TREX_RABBITMQ_TIMEOUT=5