delthin/dsh-fast: Add a Standard/Fast mode switch for DSH sessions

delthin/dsh-fast (version 0.1.2, MIT, maintainer Delthin) provides session-level standard/Fast tier switching and a model selector with reasoning level adjustment for DeepSeek Harness. The Fast tier routes requests from an explicitly configured provider to a precisely matching Responses URL, forwards them to a specified Codex Responses URL, and sets `service_tier: priority`. It requires a host of at least DSH 0.2.1-rc.5 (Web), Node 22.19.0+, and has fixed dependencies undici@7.30.1 and zod@4.6.7. Install via `dsh plugin --profile web add @delthin/dsh-fast@0.1.2` or the GitHub Release zip package of the same version. It must be configured with `provider`, `sourceURL`, and `targetURL` in the profile's `fast` entry to function; the optional `roleRunsPath` links with the character plugin to start a snapshot. The plugin runs with the current dsh process permissions, and forwarding includes the original adapter's authentication credentials, so the target must be trusted and authorized to receive them.