feat(billing): 完成异步结算与请求执行闭环

统一任务成功、Attempt 与结算 Outbox 的事务边界，增加多实例安全结算、人工复核、请求幂等与执行租约。钱包决策使用九位精确金额，并通过审计保护约束保留流水事实；同时补充管理接口、指标与 PostgreSQL 集成测试。

apps/api/migrations/0069_billing_correctness_v2.sql

@@ -1,16 +1,24 @@
 ALTER TABLE gateway_tasks
-  ADD COLUMN IF NOT EXISTS billing_version text NOT NULL DEFAULT 'effective-pricing-v2',
-  ADD COLUMN IF NOT EXISTS billing_status text NOT NULL DEFAULT 'not_started',
-  ADD COLUMN IF NOT EXISTS billing_currency text NOT NULL DEFAULT 'resource',
-  ADD COLUMN IF NOT EXISTS pricing_snapshot jsonb NOT NULL DEFAULT '{}'::jsonb,
+  ADD COLUMN IF NOT EXISTS billing_version text DEFAULT 'effective-pricing-v2',
+  ADD COLUMN IF NOT EXISTS billing_status text DEFAULT 'not_started',
+  ADD COLUMN IF NOT EXISTS billing_currency text DEFAULT 'resource',
+  ADD COLUMN IF NOT EXISTS pricing_snapshot jsonb DEFAULT '{}'::jsonb,
   ADD COLUMN IF NOT EXISTS request_fingerprint text,
   ADD COLUMN IF NOT EXISTS idempotency_key_hash text,
-  ADD COLUMN IF NOT EXISTS reservation_amount numeric(38, 9) NOT NULL DEFAULT 0,
+  ADD COLUMN IF NOT EXISTS idempotency_request_hash text,
+  ADD COLUMN IF NOT EXISTS reservation_amount numeric(38, 9) DEFAULT 0,
   ADD COLUMN IF NOT EXISTS execution_token uuid,
   ADD COLUMN IF NOT EXISTS execution_lease_expires_at timestamptz,
   ADD COLUMN IF NOT EXISTS billing_updated_at timestamptz,
   ADD COLUMN IF NOT EXISTS billing_settled_at timestamptz;
 
+UPDATE gateway_tasks
+SET billing_version = COALESCE(billing_version, 'effective-pricing-v2'),
+    billing_status = COALESCE(billing_status, 'not_started'),
+    billing_currency = COALESCE(billing_currency, 'resource'),
+    pricing_snapshot = COALESCE(pricing_snapshot, '{}'::jsonb),
+    reservation_amount = COALESCE(reservation_amount, 0);
+
 ALTER TABLE gateway_tasks
   ADD CONSTRAINT gateway_tasks_billing_status_v2_check CHECK (
     billing_status IN (
@@ -32,28 +40,40 @@ CREATE INDEX IF NOT EXISTS idx_gateway_tasks_billing_status_v2
   ON gateway_tasks(billing_status, billing_updated_at, created_at);
 
 ALTER TABLE gateway_task_attempts
-  ADD COLUMN IF NOT EXISTS pricing_snapshot jsonb NOT NULL DEFAULT '{}'::jsonb,
+  ADD COLUMN IF NOT EXISTS pricing_snapshot jsonb DEFAULT '{}'::jsonb,
   ADD COLUMN IF NOT EXISTS request_fingerprint text,
-  ADD COLUMN IF NOT EXISTS upstream_submission_status text NOT NULL DEFAULT 'not_submitted',
+  ADD COLUMN IF NOT EXISTS upstream_submission_status text DEFAULT 'not_submitted',
   ADD COLUMN IF NOT EXISTS upstream_submission_updated_at timestamptz;
 
+UPDATE gateway_task_attempts
+SET pricing_snapshot = COALESCE(pricing_snapshot, '{}'::jsonb),
+    upstream_submission_status = COALESCE(upstream_submission_status, 'not_submitted');
+
 ALTER TABLE gateway_task_attempts
   ADD CONSTRAINT gateway_task_attempts_submission_v2_check CHECK (
     upstream_submission_status IN ('not_submitted', 'submitting', 'response_received')
   ) NOT VALID;
 
 ALTER TABLE settlement_outbox
-  ADD COLUMN IF NOT EXISTS action text NOT NULL DEFAULT 'settle',
-  ADD COLUMN IF NOT EXISTS amount numeric(38, 9) NOT NULL DEFAULT 0,
-  ADD COLUMN IF NOT EXISTS currency text NOT NULL DEFAULT 'resource',
-  ADD COLUMN IF NOT EXISTS pricing_snapshot jsonb NOT NULL DEFAULT '{}'::jsonb,
+  ADD COLUMN IF NOT EXISTS action text DEFAULT 'settle',
+  ADD COLUMN IF NOT EXISTS amount numeric(38, 9) DEFAULT 0,
+  ADD COLUMN IF NOT EXISTS currency text DEFAULT 'resource',
+  ADD COLUMN IF NOT EXISTS pricing_snapshot jsonb DEFAULT '{}'::jsonb,
   ADD COLUMN IF NOT EXISTS locked_by text,
   ADD COLUMN IF NOT EXISTS lock_token uuid,
   ADD COLUMN IF NOT EXISTS locked_at timestamptz,
   ADD COLUMN IF NOT EXISTS last_error_code text,
   ADD COLUMN IF NOT EXISTS last_error_message text,
   ADD COLUMN IF NOT EXISTS completed_at timestamptz,
-  ADD COLUMN IF NOT EXISTS manual_review_reason text;
+  ADD COLUMN IF NOT EXISTS manual_review_reason text,
+  ADD COLUMN IF NOT EXISTS retry_idempotency_key_hash text,
+  ADD COLUMN IF NOT EXISTS retry_requested_at timestamptz;
+
+UPDATE settlement_outbox
+SET action = COALESCE(action, 'settle'),
+    amount = COALESCE(amount, 0),
+    currency = COALESCE(currency, 'resource'),
+    pricing_snapshot = COALESCE(pricing_snapshot, '{}'::jsonb);
 
 ALTER TABLE settlement_outbox
   ADD CONSTRAINT settlement_outbox_action_v2_check CHECK (action IN ('settle', 'release')) NOT VALID,
@@ -71,7 +91,9 @@ CREATE INDEX IF NOT EXISTS idx_settlement_outbox_stale_v2
   WHERE status = 'processing';
 
 ALTER TABLE model_pricing_rules
-  ADD COLUMN IF NOT EXISTS is_free boolean NOT NULL DEFAULT false;
+  ADD COLUMN IF NOT EXISTS is_free boolean DEFAULT false;
+
+UPDATE model_pricing_rules SET is_free = false WHERE is_free IS NULL;
 
 ALTER TABLE model_pricing_rules
   ADD CONSTRAINT model_pricing_rules_explicit_free_v2_check CHECK (
@@ -82,9 +104,18 @@ ALTER TABLE gateway_wallet_accounts
   ADD CONSTRAINT gateway_wallet_nonnegative_frozen_v2_check CHECK (frozen_balance >= 0) NOT VALID,
   ADD CONSTRAINT gateway_wallet_balance_covers_frozen_v2_check CHECK (balance >= frozen_balance) NOT VALID;
 
+CREATE TABLE IF NOT EXISTS gateway_wallet_account_audit_guards (
+  account_id uuid PRIMARY KEY REFERENCES gateway_wallet_accounts(id) ON DELETE RESTRICT,
+  created_at timestamptz NOT NULL DEFAULT now()
+);
+
+INSERT INTO gateway_wallet_account_audit_guards (account_id)
+SELECT id FROM gateway_wallet_accounts
+ON CONFLICT (account_id) DO NOTHING;
+
 ALTER TABLE gateway_wallet_transactions
-  ADD CONSTRAINT gateway_wallet_transactions_account_restrict_v2
-  FOREIGN KEY (account_id) REFERENCES gateway_wallet_accounts(id) ON DELETE RESTRICT NOT VALID;
+  ADD CONSTRAINT gateway_wallet_transactions_audit_guard_v2
+  FOREIGN KEY (account_id) REFERENCES gateway_wallet_account_audit_guards(account_id) ON DELETE RESTRICT NOT VALID;
 
 UPDATE gateway_tasks task
 SET billing_status = 'not_required',