Remove third-party compression dependencies

[rexzhang]

• remove brotli
• add zstd
• Compression level to numeric value (user-controlled), BROKED CHANGE
• Implemented after the release of py3.14

[rexzhang]

• py3.14+ environment activates zstd by default
• In older python environments, if the user activates zstd via configuration, the program exits after logging an error.

[rexzhang]

• 支持通过配置完全禁用压缩;将压缩的行为交给反向代理,比如 nginx

[rexzhang]

• fa8243e 已支持禁用压缩

[rexzhang]

ddc193e

• 使用 backports.zstd 在 3.14 以前版本支持 zstd 压缩
• brotli 已经移除
• 等待 dataclass-wizard 发布新版本支持 3.14, 已经捐献代码 Compatible with py3.14 rnag/dataclass-wizard#204