refactor: 大规模模块拆分与代码精简，新增 ai-pipeline/data-contracts 独立 crate

- 新增 aether-ai-pipeline 和 aether-data-contracts crate，将 pipeline 逻辑与数据契约从 gateway 中解耦
- 重构 admin handlers：拆分单体模块为 auth/billing/endpoint/features/model/observability/provider/system 等独立子模块
- 合并 chat/cli 重复代码路径：精简 conversion、finalize、planner 中的 sync/chat/cli 分支
- 重构 scheduler/executor/data 层，引入 facade 模式降低模块间耦合
- 移除冗余的 intent 模块，将 plan_fallback/policy/stream_path/sync_path 迁移至 executor
- 前端适配：调整 admin API 调用和 provider 模型测试对话框

apps/aether-gateway/src/log_ids.rs

@@ -0,0 +1,74 @@
+pub(crate) fn short_request_id(value: &str) -> String {
+    let trimmed = value.trim();
+    if trimmed.is_empty() {
+        return "-".to_string();
+    }
+
+    if trimmed.chars().count() <= 12 {
+        return trimmed.to_string();
+    }
+
+    if looks_like_uuid(trimmed) {
+        return trimmed.chars().take(8).collect();
+    }
+
+    let prefix: String = trimmed.chars().take(6).collect();
+    let suffix: String = trimmed
+        .chars()
+        .rev()
+        .take(4)
+        .collect::<String>()
+        .chars()
+        .rev()
+        .collect();
+    format!("{prefix}...{suffix}")
+}
+
+fn looks_like_uuid(value: &str) -> bool {
+    let bytes = value.as_bytes();
+    if bytes.len() != 36 {
+        return false;
+    }
+
+    for (index, byte) in bytes.iter().enumerate() {
+        let is_hyphen = matches!(index, 8 | 13 | 18 | 23);
+        if is_hyphen {
+            if *byte != b'-' {
+                return false;
+            }
+            continue;
+        }
+
+        if !byte.is_ascii_hexdigit() {
+            return false;
+        }
+    }
+
+    true
+}
+
+#[cfg(test)]
+mod tests {
+    use super::short_request_id;
+
+    #[test]
+    fn shortens_uuid_like_request_ids_to_prefix() {
+        assert_eq!(
+            short_request_id("d07e1e94-41b8-409f-a18a-27993ae7ecb1"),
+            "d07e1e94"
+        );
+    }
+
+    #[test]
+    fn shortens_long_named_request_ids_to_prefix_and_suffix() {
+        assert_eq!(
+            short_request_id("trace-openai-cli-stream-sync-direct-123"),
+            "trace-...-123"
+        );
+    }
+
+    #[test]
+    fn preserves_short_request_ids() {
+        assert_eq!(short_request_id("req-123"), "req-123");
+    }
+}