feat: postgres history-first 계약과 적재 경로 추가

- PostgreSQL history contract와 schema/validator를 추가했습니다.
- .NET history store, snapshot reader, repository, migration을 연결했습니다.
- history-first 운영 모델 문서와 daily signal tracking 문구를 정리했습니다.

src/dotnet/QuantEngine.Infrastructure/Data/DbMigrator.cs

@@ -156,6 +156,87 @@ namespace QuantEngine.Infrastructure.Data
                     PRIMARY KEY (domain, target_ref)
                 );
             ");
+
+            // 10. engine_history schema and tables
+            conn.Execute(@"
+                CREATE SCHEMA IF NOT EXISTS engine_history;
+            ");
+            conn.Execute(@"
+                CREATE TABLE IF NOT EXISTS engine_history.market_raw_history (
+                    id BIGSERIAL PRIMARY KEY,
+                    source_id TEXT NOT NULL,
+                    observed_at TEXT NOT NULL,
+                    source_name TEXT NOT NULL,
+                    instrument_id TEXT NOT NULL,
+                    field_name TEXT NOT NULL,
+                    field_value TEXT NOT NULL,
+                    unit TEXT NOT NULL,
+                    provenance JSONB NOT NULL DEFAULT '{}'::jsonb,
+                    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+                );
+                CREATE INDEX IF NOT EXISTS idx_market_raw_history_created_at ON engine_history.market_raw_history (created_at DESC);
+            ");
+            conn.Execute(@"
+                CREATE TABLE IF NOT EXISTS engine_history.factor_version_history (
+                    id BIGSERIAL PRIMARY KEY,
+                    factor_id TEXT NOT NULL,
+                    factor_version TEXT NOT NULL,
+                    effective_from TEXT NOT NULL,
+                    effective_to TEXT NOT NULL,
+                    formula_id TEXT NOT NULL,
+                    source_version TEXT NOT NULL,
+                    provenance JSONB NOT NULL DEFAULT '{}'::jsonb,
+                    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+                );
+                CREATE INDEX IF NOT EXISTS idx_factor_version_history_created_at ON engine_history.factor_version_history (created_at DESC);
+            ");
+            conn.Execute(@"
+                CREATE TABLE IF NOT EXISTS engine_history.factor_output_history (
+                    id BIGSERIAL PRIMARY KEY,
+                    factor_output_id TEXT NOT NULL,
+                    observed_at TEXT NOT NULL,
+                    factor_id TEXT NOT NULL,
+                    factor_version TEXT NOT NULL,
+                    output_value TEXT NOT NULL,
+                    output_gate TEXT NOT NULL,
+                    source_version TEXT NOT NULL,
+                    provenance JSONB NOT NULL DEFAULT '{}'::jsonb,
+                    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+                );
+                CREATE INDEX IF NOT EXISTS idx_factor_output_history_created_at ON engine_history.factor_output_history (created_at DESC);
+            ");
+            conn.Execute(@"
+                CREATE TABLE IF NOT EXISTS engine_history.decision_result_history (
+                    id BIGSERIAL PRIMARY KEY,
+                    decision_id TEXT NOT NULL,
+                    decided_at TEXT NOT NULL,
+                    instrument_id TEXT NOT NULL,
+                    action TEXT NOT NULL,
+                    gate TEXT NOT NULL,
+                    score TEXT NOT NULL,
+                    source_version TEXT NOT NULL,
+                    provenance JSONB NOT NULL DEFAULT '{}'::jsonb,
+                    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+                );
+                CREATE INDEX IF NOT EXISTS idx_decision_result_history_created_at ON engine_history.decision_result_history (created_at DESC);
+            ");
+            conn.Execute(@"
+                CREATE TABLE IF NOT EXISTS engine_history.market_vs_engine_gap_history (
+                    id BIGSERIAL PRIMARY KEY,
+                    gap_id TEXT NOT NULL,
+                    observed_at TEXT NOT NULL,
+                    instrument_id TEXT NOT NULL,
+                    metric_name TEXT NOT NULL,
+                    market_value TEXT NOT NULL,
+                    engine_value TEXT NOT NULL,
+                    gap_value TEXT NOT NULL,
+                    gap_pct TEXT NOT NULL,
+                    source_version TEXT NOT NULL,
+                    provenance JSONB NOT NULL DEFAULT '{}'::jsonb,
+                    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+                );
+                CREATE INDEX IF NOT EXISTS idx_market_vs_engine_gap_history_created_at ON engine_history.market_vs_engine_gap_history (created_at DESC);
+            ");
         }
     }
 }