Add DeepSeek Harness as a supported skills provider (#746)

* Add DeepSeek Harness as a supported skills provider

npx impeccable install now detects ~/.dsh (or $DSH_HOME when it sits
under home) and installs into ~/.dsh/skills, the user-level skill root
DeepSeek Harness scans, with project-level .dsh/skills on the same
layout as other providers. Aliases: dsh, deepseek, deepseek-harness.

Engine: PROVIDER_DIRS / aliases / display / input order / global hint,
$DSH_HOME-aware user skills dir, provider id resolution from the skill
dir, pin harness dirs, bundle path normalization for hashing.

Build: dsh transformer target emitting the frontmatter DeepSeek Harness
reads (user-invocable, license, compatibility, metadata; unknown keys
are ignored there) with no emitHooks (DSH hooks are in-process plugins,
not on-disk manifests) and no agentFormat (no documented on-disk
subagent format); placeholders (AGENTS.md config file, ask_user_question
tool, / command prefix), provider block tags, universal README entry.

Docs: HARNESSES.md row and frontmatter column, CLI-CONTRACT constants,
README/DEVELOP/AGENTS provider lists.

Validation: cargo test --workspace; node scripts/run-tests.mjs core
(138 pass); bun run build (19 providers, dist/dsh artifact verified);
engine smoke against a fake HOME with a local bundle: install
--providers=dsh --scope=global, auto-detected install, and update all
resolve the .dsh provider.

Generated provider output intentionally omitted per repo policy; the
sync workflow regenerates tracked .dsh/skills after merge.

Prepared with AI assistance (DeepSeek Harness coding agent).

* Address review: DSH_HOME-only detection, generated-output pathspecs

- Detect DeepSeek Harness through the resolved $DSH_HOME (fallback
  ~/.dsh) instead of gating on a fixed ~/.dsh path, so a DSH_HOME-only
  setup is offered by a provider-less install; generalize the two
  env-relocated config-dir hints (OpenCode, DSH) into one shared probe.
- Add .dsh to the sync workflow's GENERATED_PATHS and CI's generated
  drift check so the tracked .dsh/skills payload is committed and
  validated.
- Cover both behaviors: new install_detection_tests (DSH_HOME-only,
  default ~/.dsh, refused outside-home override) and a CLI-CONTRACT
  note on the resolved detection path.

Validation: cargo test --workspace; node scripts/run-tests.mjs core
(138 pass); engine smoke: DSH_HOME-only fake HOME installs globally
into the resolved skills dir.

Prepared with AI assistance (DeepSeek Harness coding agent).

* Fix DeepSeek Harness home paths on Windows

Use native relative-path containment, cover case and drive boundaries, and verify relocated global install/update without changing project skills. Add DSH output coverage and correct the install documentation.

AI assistance: Codex, under pbakaus maintainer direction.

* Document the CLI limit on external DSH homes

Clarify that outside-home manual copies are not detected or updated by the CLI.

AI assistance: Codex, under pbakaus maintainer direction.

---------

Co-authored-by: Paul Bakaus <paul.bakaus@gmail.com>

crates/context/src/pin.rs

@@ -8,8 +8,8 @@ use impeccable_common::Io;
 /// keep in sync with the public repo).
 pub const COMMAND_METADATA_JSON: &str = include_str!("command-metadata.json");
 
-const HARNESS_DIRS: [&str; 17] = [
-    ".claude", ".cursor", ".gemini", ".codex", ".agents", ".agent", ".github", ".grok", ".hermes", ".trae", ".trae-cn",
+const HARNESS_DIRS: [&str; 18] = [
+    ".claude", ".cursor", ".dsh", ".gemini", ".codex", ".agents", ".agent", ".github", ".grok", ".hermes", ".trae", ".trae-cn",
     ".pi", ".opencode", ".kiro", ".rovodev", ".vibe", ".qoder",
 ];
 const CODEX_HARNESSES: [&str; 2] = [".codex", ".agents"];

crates/context/src/provider.rs

@@ -62,6 +62,7 @@ fn provider_from_skill_dir(skill_dir: &str) -> Option<&'static str> {
     Some(match harness.as_str() {
         ".claude" => "claude-code",
         ".cursor" => "cursor",
+        ".dsh" => "dsh",
         ".gemini" => "gemini",
         ".codex" => "codex",
         ".agents" => "agents",