refactor(postgres models): remove unnecessary indexes and add new fields and indexes

1. 移除 ExternalSystemHealthCheck、ExternalSystemQuotaUsage、ExternalToolTestCase 中的冗余索引
2. 为 ChannelUserIdentity 新增 pending_review 字段并添加GIN索引加速查询
3. 为 ChannelAuditLog 添加 target_account 字段索引
4. 为 ChannelOutboxEntry 新增 delivered_parts 字段并添加高频查询列索引

backend/package/yuxi/storage/postgres/models_channels.py

@@ -284,9 +284,10 @@ class ChannelUserIdentity(Base):
         default=dict,
         comment="渠道绑定映射：{channel_type: [peer_id, ...]}",
     )
-    merged_from = Column(JSON_VALUE, nullable=False, default=list, comment="合并来源 identity_id 列表")
+    merged_from = Column(JSON_VALUE, nullable=False, default=list, comment="合并来源结构化证据列表")
     confidence = Column(String(16), nullable=False, default="low", comment="身份置信度：low/medium/high")
     version = Column(Integer, nullable=False, default=1, comment="乐观锁版本号")
+    pending_review = Column(Boolean, nullable=False, default=False, comment="低置信度合并待审批标记（H-21）")
 
     # 审计字段
     created_by = Column(String(64), nullable=True)
@@ -306,6 +307,19 @@ class ChannelUserIdentity(Base):
             unique=True,
             postgresql_where=text("is_deleted = 0"),
         ),
+        # GIN 索引：加速 channel_bindings / merged_from 的 @> 包含查询
+        Index(
+            "ix_channel_user_identities_channel_bindings_gin",
+            "channel_bindings",
+            postgresql_using="gin",
+            postgresql_ops={"channel_bindings": "jsonb_path_ops"},
+        ),
+        Index(
+            "ix_channel_user_identities_merged_from_gin",
+            "merged_from",
+            postgresql_using="gin",
+            postgresql_ops={"merged_from": "jsonb_path_ops"},
+        ),
     )
 
     def to_dict(self) -> dict[str, Any]:
@@ -323,6 +337,7 @@ class ChannelUserIdentity(Base):
             "merged_from": self.merged_from or [],
             "confidence": self.confidence,
             "version": self.version,
+            "pending_review": self.pending_review,
             "created_by": self.created_by,
             "updated_by": self.updated_by,
             "created_at": format_utc_datetime(self.created_at),
@@ -481,6 +496,9 @@ class ChannelAuditLog(Base):
         Index("ix_channel_audit_logs_operation_time", "operation", "timestamp"),
         Index("ix_channel_audit_logs_operator_time", "operator", "timestamp"),
         Index("ix_channel_audit_logs_target_time", "target_channel", "timestamp"),
+        # 高频过滤列索引（H-8）：target_account 为审计日志查询的高频过滤条件，
+        # 无索引会触发全表扫描。
+        Index("ix_channel_audit_logs_target_account", "target_account"),
     )
 
     def to_dict(self) -> dict[str, Any]:
@@ -614,6 +632,13 @@ class ChannelOutboxEntry(Base):
         nullable=True,
         comment="降级原因摘要（BEST_EFFORT 持久化失败、markDeliveryUnconfirmedFailed 等）",
     )
+    delivered_parts = Column(
+        JSONB,
+        nullable=False,
+        default=list,
+        server_default="[]",
+        comment="多分片投递已成功投递的分片序号列表，重试时仅发送未投递分片（H-15）",
+    )
 
     # 过期与追踪
     expires_at = Column(DateTime, nullable=False, comment="过期时间（默认创建时间 + 24h）")
@@ -635,6 +660,10 @@ class ChannelOutboxEntry(Base):
         Index("ix_channel_outbox_locked_at", "locked_at"),
         Index("ix_channel_outbox_latency_ms", "latency_ms"),
         Index("ix_channel_outbox_funnel_node", "funnel_node"),
+        # 外键列索引（H-8）：_applyOutboxQueryFilter 按 channel_session_id 过滤，
+        # conversation_id 为高频 JOIN/级联列，无索引会触发全表扫描。
+        Index("ix_channel_outbox_channel_session", "channel_session_id"),
+        Index("ix_channel_outbox_conversation", "conversation_id"),
     )
 
     def to_dict(self) -> dict[str, Any]:
@@ -666,6 +695,7 @@ class ChannelOutboxEntry(Base):
             "partial_failure": self.partial_failure,
             "stream_aborted_at_chunk": self.stream_aborted_at_chunk,
             "degraded_reason": self.degraded_reason,
+            "delivered_parts": self.delivered_parts,
             "expires_at": format_utc_datetime(self.expires_at),
             "trace_id": self.trace_id,
             "version": self.version,

backend/package/yuxi/storage/postgres/models_external.py

@@ -744,7 +744,7 @@ class ExternalSystemHealthCheck(Base):
     detail = Column(Text, nullable=True, comment="探测结果说明")
     error_code = Column(String(64), nullable=True, comment="错误码")
     error_message = Column(Text, nullable=True, comment="错误信息")
-    checked_at = Column(DateTime, nullable=True, index=True, comment="探测时间")
+    checked_at = Column(DateTime, nullable=True, comment="探测时间")
 
     # 审计字段
     created_by = Column(String(64), nullable=True)
@@ -1023,7 +1023,7 @@ class ExternalSystemQuotaUsage(Base):
     quota_name = Column(String(128), nullable=False, comment="配额展示名称")
     quota_window = Column(String(32), nullable=False, comment="窗口类型：daily/hourly/rolling_24h/minute/custom")
     window_start = Column(DateTime, nullable=True, comment="窗口起始时间")
-    window_end = Column(DateTime, nullable=True, index=True, comment="窗口结束时间（重置时间）")
+    window_end = Column(DateTime, nullable=True, comment="窗口结束时间（重置时间）")
 
     # 配额数值
     limit_value = Column(BigInteger, nullable=False, default=0, comment="配额上限")
@@ -1440,7 +1440,7 @@ class ExternalToolTestCase(Base):
 
     # 上次运行结果
     last_run_at = Column(DateTime, nullable=True, comment="上次运行时间")
-    last_run_status = Column(String(32), nullable=True, index=True, comment="上次运行结果：passed/failed/error/skipped")
+    last_run_status = Column(String(32), nullable=True, comment="上次运行结果：passed/failed/error/skipped")
     last_run_duration_ms = Column(Integer, nullable=True, comment="上次运行耗时毫秒")
     last_run_response = Column(JSON_VALUE, nullable=True, comment="上次运行响应（已脱敏）")
     last_run_error = Column(Text, nullable=True, comment="上次运行错误信息")