dsh-encoding: Encoding Error Correction and Garbled Text Recovery for DeepSeek Harness

DeepSeek Harness (DSH) produces garbled Chinese text on Windows due to forced decoding. The dsh-encoding plugin resolves this issue by providing standalone `encoding_run` (execute and automatically decode) and `encoding_decode` (repair garbled text) tools. It is zero-dependency, pure ESM, and requires no build, while correctly handling UTF-8, UTF-16LE, and GBK encodings. It does not replace built-in tools but operates as a supplement; users should note its detection limitations and data size limits.