feat(api): support traffic bytes tracking in edge access logs and refactor analytics models

- Add `bytes_sent` to `NodeAccessLog` on both Agent and Master Server.
- Create ClickHouse migration `202607120001_add_bytes_sent_to_node_access_logs.sql`.
- Refactor duplicate stats structs by centralizing them into `analyticsmodel` package with type aliases.
- Simplify access log store delegations and remove redundant mapping loops.
- Regenerate Swagger documentation.
- Update changelog index.md.

internal/db/migrator/goose/clickhouse/202607120001_add_bytes_sent_to_node_access_logs.sql

@@ -0,0 +1,5 @@
+-- +goose Up
+ALTER TABLE of_node_access_logs ADD COLUMN IF NOT EXISTS bytes_sent UInt64;
+
+-- +goose Down
+ALTER TABLE of_node_access_logs DROP COLUMN IF EXISTS bytes_sent;