Add multi-database data layer

Introduce aether-data-schema and driver-specific schema generation for Postgres, MySQL, and SQLite.

Split data backends, lifecycle, repositories, and gateway runtime integration across database drivers.

Verified with cargo fmt --all --check, cargo clippy --workspace --all-targets -- -D warnings, and cargo test --workspace.

apps/aether-gateway/src/handlers/admin/billing/mod.rs

@@ -1,5 +1,5 @@
 use crate::handlers::admin::request::{AdminAppState, AdminRequestContext};
-use crate::handlers::admin::shared::{query_param_value, unix_secs_to_rfc3339};
+use crate::handlers::admin::shared::query_param_value;
 use crate::GatewayError;
 use axum::{
     body::{Body, Bytes},
@@ -9,7 +9,6 @@ use axum::{
 };
 use regex::Regex;
 use serde_json::json;
-use sqlx::Row;
 
 const ADMIN_BILLING_DATA_UNAVAILABLE_DETAIL: &str = "Admin billing data unavailable";
 
@@ -185,20 +184,6 @@ fn admin_billing_validate_safe_expression(expression: &str) -> Result<(), String
     Ok(())
 }
 
-fn admin_billing_optional_epoch_value(
-    row: &sqlx::postgres::PgRow,
-    field: &str,
-) -> Result<Option<String>, GatewayError> {
-    let value = row
-        .try_get::<Option<i64>, _>(field)
-        .map_err(|err| GatewayError::Internal(err.to_string()))?;
-    match value {
-        None => Ok(None),
-        Some(value) if value < 0 => Ok(None),
-        Some(value) => Ok(unix_secs_to_rfc3339(value as u64)),
-    }
-}
-
 pub(crate) async fn maybe_build_local_admin_billing_response(
     state: &AdminAppState<'_>,
     request_context: &AdminRequestContext<'_>,

apps/aether-gateway/src/handlers/admin/billing/payments/callbacks.rs

@@ -1,7 +1,6 @@
 use super::{
-    build_admin_payment_callback_payload, build_admin_payment_callback_payload_from_record,
-    build_admin_payments_bad_request_response, parse_admin_payments_limit,
-    parse_admin_payments_offset,
+    build_admin_payment_callback_payload_from_record, build_admin_payments_bad_request_response,
+    parse_admin_payments_limit, parse_admin_payments_offset,
 };
 use crate::handlers::admin::request::{AdminAppState, AdminRequestContext};
 use crate::handlers::admin::shared::query_param_value;

apps/aether-gateway/src/handlers/admin/billing/payments/mod.rs

@@ -12,13 +12,13 @@ mod shared;
 
 use self::shared::{
     admin_payment_operator_id, admin_payment_order_id_from_detail_path,
-    admin_payment_order_id_from_suffix_path, build_admin_payment_callback_payload,
-    build_admin_payment_callback_payload_from_record, build_admin_payment_order_not_found_response,
-    build_admin_payment_order_payload, build_admin_payment_orders_page_response,
-    build_admin_payments_backend_unavailable_response, build_admin_payments_bad_request_response,
-    build_admin_payments_data_unavailable_response, normalize_admin_payment_currency,
-    normalize_admin_payment_optional_string, normalize_admin_payment_positive_number,
-    parse_admin_payments_limit, parse_admin_payments_offset, AdminPaymentOrderCreditRequest,
+    admin_payment_order_id_from_suffix_path, build_admin_payment_callback_payload_from_record,
+    build_admin_payment_order_not_found_response, build_admin_payment_order_payload,
+    build_admin_payment_orders_page_response, build_admin_payments_backend_unavailable_response,
+    build_admin_payments_bad_request_response, build_admin_payments_data_unavailable_response,
+    normalize_admin_payment_currency, normalize_admin_payment_optional_string,
+    normalize_admin_payment_positive_number, parse_admin_payments_limit,
+    parse_admin_payments_offset, AdminPaymentOrderCreditRequest,
 };
 
 pub(crate) async fn maybe_build_local_admin_payments_response(

apps/aether-gateway/src/handlers/admin/billing/payments/shared.rs

@@ -1,6 +1,6 @@
 use crate::handlers::admin::request::AdminRequestContext;
 use crate::handlers::admin::shared::{query_param_value, unix_secs_to_rfc3339};
-use crate::{GatewayAdminPaymentCallbackView, GatewayError};
+use crate::GatewayAdminPaymentCallbackView;
 use axum::{
     body::Body,
     http,
@@ -8,7 +8,6 @@ use axum::{
     Json,
 };
 use serde_json::json;
-use sqlx::Row;
 
 const ADMIN_PAYMENTS_DATA_UNAVAILABLE_DETAIL: &str = "Admin payments data unavailable";
 
@@ -220,34 +219,6 @@ pub(super) fn build_admin_payment_order_payload(
     })
 }
 
-pub(super) fn build_admin_payment_callback_payload(
-    row: &sqlx::postgres::PgRow,
-) -> Result<serde_json::Value, GatewayError> {
-    Ok(json!({
-        "id": row.try_get::<String, _>("id").map_err(|err| GatewayError::Internal(err.to_string()))?,
-        "payment_order_id": row.try_get::<Option<String>, _>("payment_order_id").map_err(|err| GatewayError::Internal(err.to_string()))?,
-        "payment_method": row.try_get::<String, _>("payment_method").map_err(|err| GatewayError::Internal(err.to_string()))?,
-        "callback_key": row.try_get::<String, _>("callback_key").map_err(|err| GatewayError::Internal(err.to_string()))?,
-        "order_no": row.try_get::<Option<String>, _>("order_no").map_err(|err| GatewayError::Internal(err.to_string()))?,
-        "gateway_order_id": row.try_get::<Option<String>, _>("gateway_order_id").map_err(|err| GatewayError::Internal(err.to_string()))?,
-        "payload_hash": row.try_get::<Option<String>, _>("payload_hash").map_err(|err| GatewayError::Internal(err.to_string()))?,
-        "signature_valid": row.try_get::<bool, _>("signature_valid").map_err(|err| GatewayError::Internal(err.to_string()))?,
-        "status": row.try_get::<String, _>("status").map_err(|err| GatewayError::Internal(err.to_string()))?,
-        "payload": row.try_get::<Option<serde_json::Value>, _>("payload").map_err(|err| GatewayError::Internal(err.to_string()))?,
-        "error_message": row.try_get::<Option<String>, _>("error_message").map_err(|err| GatewayError::Internal(err.to_string()))?,
-        "created_at": row
-            .try_get::<Option<i64>, _>("created_at_unix_ms")
-            .map_err(|err| GatewayError::Internal(err.to_string()))?
-            .and_then(|value| u64::try_from(value).ok())
-            .and_then(unix_secs_to_rfc3339),
-        "processed_at": row
-            .try_get::<Option<i64>, _>("processed_at_unix_secs")
-            .map_err(|err| GatewayError::Internal(err.to_string()))?
-            .and_then(|value| u64::try_from(value).ok())
-            .and_then(unix_secs_to_rfc3339),
-    }))
-}
-
 pub(super) fn build_admin_payment_callback_payload_from_record(
     record: &GatewayAdminPaymentCallbackView,
 ) -> serde_json::Value {

apps/aether-gateway/src/handlers/admin/billing/wallets/mutations/adjust.rs

@@ -61,7 +61,7 @@ pub(in super::super) async fn build_admin_wallet_adjust_response(
         ));
     }
     let operator_id = admin_wallet_operator_id(request_context);
-    let has_postgres = state.has_postgres_pool();
+    let has_wallet_writer = state.has_wallet_data_writer();
     let Some((wallet, transaction)) = state
         .admin_adjust_wallet_balance(
             &wallet_id,
@@ -72,7 +72,7 @@ pub(in super::super) async fn build_admin_wallet_adjust_response(
         )
         .await?
     else {
-        return if has_postgres {
+        return if has_wallet_writer {
             Ok(build_admin_wallet_not_found_response())
         } else {
             Ok(build_admin_wallets_data_unavailable_response())

apps/aether-gateway/src/handlers/admin/billing/wallets/mutations/recharge.rs

@@ -61,7 +61,7 @@ pub(in super::super) async fn build_admin_wallet_recharge_response(
         ));
     }
     let operator_id = admin_wallet_operator_id(request_context);
-    let has_postgres = state.has_postgres_pool();
+    let has_wallet_writer = state.has_wallet_data_writer();
     let Some((wallet, payment_order)) = state
         .admin_create_manual_wallet_recharge(
             &wallet_id,
@@ -72,7 +72,7 @@ pub(in super::super) async fn build_admin_wallet_recharge_response(
         )
         .await?
     else {
-        return if has_postgres {
+        return if has_wallet_writer {
             Ok(build_admin_wallet_not_found_response())
         } else {
             Ok(build_admin_wallets_data_unavailable_response())

apps/aether-gateway/src/handlers/admin/billing/wallets/shared/support.rs

@@ -1,8 +1,6 @@
 use super::requests::ADMIN_WALLETS_API_KEY_GIFT_ADJUST_DETAIL;
 use crate::handlers::admin::request::AdminRequestContext;
 use crate::handlers::admin::shared::query_param_value;
-use crate::GatewayError;
-use sqlx::Row;
 
 pub(in super::super) fn admin_wallet_operator_id(
     request_context: &AdminRequestContext<'_>,
@@ -198,17 +196,6 @@ pub(in super::super) fn parse_admin_wallets_owner_type_filter(
     }
 }
 
-pub(in super::super) fn optional_epoch_value(
-    row: &sqlx::postgres::PgRow,
-    key: &str,
-) -> Result<Option<String>, GatewayError> {
-    Ok(row
-        .try_get::<Option<i64>, _>(key)
-        .map_err(|err| GatewayError::Internal(err.to_string()))?
-        .and_then(|value| u64::try_from(value).ok())
-        .and_then(crate::handlers::admin::shared::unix_secs_to_rfc3339))
-}
-
 pub(in super::super) fn admin_wallet_build_order_no(now: chrono::DateTime<chrono::Utc>) -> String {
     format!(
         "po_{}_{}",