test(saas): Phase 1 integration tests — billing + scheduled_task + knowledge (68 tests)

- Fix TIMESTAMPTZ decode errors: add ::TEXT cast to all SELECT queries
  where Row structs use String for TIMESTAMPTZ columns (~22 locations)
- Fix Axum 0.7 route params: {id} → :id in billing/knowledge/scheduled_task routes
- Fix JSONB bind: scheduled_task INSERT uses ::jsonb cast for input_payload
- Add billing_test.rs (14 tests): plans, subscription, usage, payments, invoices
- Add scheduled_task_test.rs (12 tests): CRUD, validation, isolation
- Add knowledge_test.rs (20 tests): categories, items, versions, search, analytics, permissions
- Fix auth test regression: 6 tests were failing due to TIMESTAMPTZ type mismatch

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

crates/zclaw-saas/src/relay/service.rs

@@ -48,14 +48,14 @@ pub async fn create_relay_task(
     max_attempts: u32,
 ) -> SaasResult<RelayTaskInfo> {
     let id = uuid::Uuid::new_v4().to_string();
-    let now = chrono::Utc::now().to_rfc3339();
+    let now = chrono::Utc::now();
     let request_hash = hash_request(request_body);
     let max_attempts = max_attempts.max(1).min(5);
 
     let query = sqlx::query_as::<_, RelayTaskRow>(
         "INSERT INTO relay_tasks (id, account_id, provider_id, model_id, request_hash, request_body, status, priority, attempt_count, max_attempts, queued_at, created_at)
          VALUES ($1, $2, $3, $4, $5, $6, 'queued', $7, 0, $8, $9, $9)
-         RETURNING id, account_id, provider_id, model_id, status, priority, attempt_count, max_attempts, input_tokens, output_tokens, error_message, queued_at, started_at, completed_at, created_at"
+         RETURNING id, account_id, provider_id, model_id, status, priority, attempt_count, max_attempts, input_tokens, output_tokens, error_message, queued_at::TEXT, started_at::TEXT, completed_at::TEXT, created_at::TEXT"
     )
     .bind(&id).bind(account_id).bind(provider_id).bind(model_id)
     .bind(&request_hash).bind(request_body).bind(priority).bind(max_attempts as i64).bind(&now);
@@ -69,7 +69,7 @@ pub async fn create_relay_task(
             sqlx::query_as::<_, RelayTaskRow>(
                 "INSERT INTO relay_tasks (id, account_id, provider_id, model_id, request_hash, request_body, status, priority, attempt_count, max_attempts, queued_at, created_at)
                  VALUES ($1, $2, $3, $4, $5, $6, 'queued', $7, 0, $8, $9, $9)
-                 RETURNING id, account_id, provider_id, model_id, status, priority, attempt_count, max_attempts, input_tokens, output_tokens, error_message, queued_at, started_at, completed_at, created_at"
+                 RETURNING id, account_id, provider_id, model_id, status, priority, attempt_count, max_attempts, input_tokens, output_tokens, error_message, queued_at::TEXT, started_at::TEXT, completed_at::TEXT, created_at::TEXT"
             )
             .bind(&id).bind(account_id).bind(provider_id).bind(model_id)
             .bind(&request_hash).bind(request_body).bind(priority).bind(max_attempts as i64).bind(&now)
@@ -91,7 +91,7 @@ pub async fn create_relay_task(
 pub async fn get_relay_task(db: &PgPool, task_id: &str) -> SaasResult<RelayTaskInfo> {
     let row: Option<RelayTaskRow> =
         sqlx::query_as(
-            "SELECT id, account_id, provider_id, model_id, status, priority, attempt_count, max_attempts, input_tokens, output_tokens, error_message, queued_at, started_at, completed_at, created_at
+            "SELECT id, account_id, provider_id, model_id, status, priority, attempt_count, max_attempts, input_tokens, output_tokens, error_message, queued_at::TEXT, started_at::TEXT, completed_at::TEXT, created_at::TEXT
              FROM relay_tasks WHERE id = $1"
         )
         .bind(task_id)
@@ -117,13 +117,13 @@ pub async fn list_relay_tasks(
     let (count_sql, data_sql) = if query.status.is_some() {
         (
             "SELECT COUNT(*) FROM relay_tasks WHERE account_id = $1 AND status = $2",
-            "SELECT id, account_id, provider_id, model_id, status, priority, attempt_count, max_attempts, input_tokens, output_tokens, error_message, queued_at, started_at, completed_at, created_at
+            "SELECT id, account_id, provider_id, model_id, status, priority, attempt_count, max_attempts, input_tokens, output_tokens, error_message, queued_at::TEXT, started_at::TEXT, completed_at::TEXT, created_at::TEXT
              FROM relay_tasks WHERE account_id = $1 AND status = $2 ORDER BY created_at DESC LIMIT $3 OFFSET $4"
         )
     } else {
         (
             "SELECT COUNT(*) FROM relay_tasks WHERE account_id = $1",
-            "SELECT id, account_id, provider_id, model_id, status, priority, attempt_count, max_attempts, input_tokens, output_tokens, error_message, queued_at, started_at, completed_at, created_at
+            "SELECT id, account_id, provider_id, model_id, status, priority, attempt_count, max_attempts, input_tokens, output_tokens, error_message, queued_at::TEXT, started_at::TEXT, completed_at::TEXT, created_at::TEXT
              FROM relay_tasks WHERE account_id = $1 ORDER BY created_at DESC LIMIT $2 OFFSET $3"
         )
     };
@@ -154,7 +154,7 @@ pub async fn update_task_status(
     input_tokens: Option<i64>, output_tokens: Option<i64>,
     error_message: Option<&str>,
 ) -> SaasResult<()> {
-    let now = chrono::Utc::now().to_rfc3339();
+    let now = chrono::Utc::now();
 
     match status {
         "processing" => {