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/schema.rs

@@ -0,0 +1,110 @@
+use std::collections::BTreeMap;
+
+pub const BILLING_SNAPSHOT_SCHEMA_VERSION: &str = "2.0";
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum BillingSnapshotStatus {
+    Complete,
+    Incomplete,
+    NoRule,
+    Legacy,
+}
+
+impl BillingSnapshotStatus {
+    pub fn as_str(self) -> &'static str {
+        match self {
+            Self::Complete => "complete",
+            Self::Incomplete => "incomplete",
+            Self::NoRule => "no_rule",
+            Self::Legacy => "legacy",
+        }
+    }
+}
+
+impl std::fmt::Display for BillingSnapshotStatus {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(self.as_str())
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize)]
+pub struct BillingSnapshot {
+    pub schema_version: String,
+    pub rule_id: Option<String>,
+    pub rule_name: Option<String>,
+    pub scope: Option<String>,
+    pub expression: Option<String>,
+    pub resolved_dimensions: BTreeMap<String, serde_json::Value>,
+    pub resolved_variables: BTreeMap<String, serde_json::Value>,
+    pub cost_breakdown: BTreeMap<String, f64>,
+    pub total_cost: f64,
+    pub tier_index: Option<i64>,
+    pub tier_info: Option<serde_json::Value>,
+    pub missing_required: Vec<String>,
+    pub status: BillingSnapshotStatus,
+    pub calculated_at: String,
+    pub engine_version: String,
+}
+
+impl Default for BillingSnapshot {
+    fn default() -> Self {
+        Self {
+            schema_version: BILLING_SNAPSHOT_SCHEMA_VERSION.to_string(),
+            rule_id: None,
+            rule_name: None,
+            scope: None,
+            expression: None,
+            resolved_dimensions: BTreeMap::new(),
+            resolved_variables: BTreeMap::new(),
+            cost_breakdown: BTreeMap::new(),
+            total_cost: 0.0,
+            tier_index: None,
+            tier_info: None,
+            missing_required: Vec::new(),
+            status: BillingSnapshotStatus::NoRule,
+            calculated_at: String::new(),
+            engine_version: "2.0".to_string(),
+        }
+    }
+}
+
+impl BillingSnapshot {
+    pub fn dimensions_used(&self) -> &BTreeMap<String, serde_json::Value> {
+        &self.resolved_dimensions
+    }
+
+    pub fn cost(&self) -> f64 {
+        self.total_cost
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize)]
+pub struct CostResult {
+    pub cost: f64,
+    pub status: BillingSnapshotStatus,
+    pub snapshot: BillingSnapshot,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{BillingSnapshot, BillingSnapshotStatus};
+
+    #[test]
+    fn snapshot_aliases_dimensions_and_cost() {
+        let mut snapshot = BillingSnapshot {
+            total_cost: 1.25,
+            status: BillingSnapshotStatus::Complete,
+            ..BillingSnapshot::default()
+        };
+        snapshot
+            .resolved_dimensions
+            .insert("input_tokens".to_string(), serde_json::json!(10));
+
+        assert_eq!(snapshot.cost(), 1.25);
+        assert_eq!(
+            snapshot.dimensions_used().get("input_tokens"),
+            Some(&serde_json::json!(10))
+        );
+    }
+}