dsh-proof: Add read-only validation layer for DeepSeek Harness

dsh-proof is an independent, read-only verification layer plugin for DeepSeek Harness, maintained by EvilIrving (version 0.1.0) under the MIT license. Its core functionality involves intervening via `agent/turn-stopping` when a top-level dialogue turn is about to close, launching a read-only verifier to perform an independent verification of the results. If verification fails, the plugin sends the specific gap and subsequent steering back to the driver agent to correct the process. The plugin relies on the `subagents` service and restricts verifier permissions via `toolFilter.deny`, defaulting to blocking the use of `write`, `edit`, `bash`, and other modification tools.