feat: 扩展 Rust gateway 全功能模块，新增 billing/crypto/wallet crate 及完整数据层

- 新增 aether-billing、aether-crypto、aether-wallet 独立 crate
- aether-data 扩展 repository 层：announcements、auth_modules、billing、
  candidate_selection、gemini_file_mappings、global_models、management_tokens、
  oauth_providers、proxy_nodes、quota、users、wallet 等模块
- aether-gateway 新增 api/auth/billing/control/middleware/scheduler/usage/
  video_tasks/hooks/maintenance/model_fetch/provider_transport 等功能模块
- 重构 executor decision 和 gateway state 为模块目录结构
- 新增 gateway router、frontdoor 路由层及对应测试
- Python 侧 API 路由重构，新增 compat/support 模块
- 前端 Logo 组件更新及 Provider 管理页面调整

crates/aether-billing/src/lib.rs

@@ -0,0 +1,27 @@
+mod default_rule;
+mod formula_engine;
+mod models;
+mod precision;
+mod pricing;
+mod schema;
+mod service;
+mod token_normalization;
+mod usage_mapper;
+
+pub use default_rule::{normalize_task_type, DefaultBillingRuleGenerator, VirtualBillingRule};
+pub use formula_engine::{
+    extract_variable_names, BillingIncompleteError, ExpressionEvaluationError, FormulaEngine,
+    FormulaEvaluationResult, FormulaEvaluationStatus, UnsafeExpressionError,
+};
+pub use models::{BillingDimension, BillingUnit, CostBreakdown, StandardizedUsage};
+pub use precision::{
+    quantize_cost, quantize_display, quantize_value, BILLING_DISPLAY_PRECISION,
+    BILLING_STORAGE_PRECISION,
+};
+pub use pricing::{BillingComputation, BillingModelPricingSnapshot, BillingUsageInput};
+pub use schema::{
+    BillingSnapshot, BillingSnapshotStatus, CostResult, BILLING_SNAPSHOT_SCHEMA_VERSION,
+};
+pub use service::BillingService;
+pub use token_normalization::normalize_input_tokens_for_billing;
+pub use usage_mapper::{map_usage, map_usage_from_response, UsageMapper};