feat(skills): discover global ~/.claude/skills (#902)

The skill registry already walks workspace-local `.claude/skills` for
Claude Code interop, plus global `~/.agents/skills` and
`~/.deepseek/skills`. Picking up the global `~/.claude/skills` brings
DeepSeek TUI in line with the broader Claude-ecosystem convention so
users can inherit skills installed for other Claude-compatible tools
without re-authoring them in DeepSeek's native layout.

Adds `claude_global_skills_dir()` mirroring `agents_global_skills_dir()`
and inserts it into `skills_directories()` between the agentskills.io
global and the DeepSeek-native global. Workspace candidates still win
on name conflicts; first-match-wins is preserved.

Tests:
- claude_global_skills_dir_returns_home_relative_path
- existing_skill_dirs_orders_globals_agents_then_claude_then_deepseek
- All 55 pre-existing skills tests still pass

Docs synced (README publishing-skills section, CONFIGURATION).
docs/COMPETITIVE_ANALYSIS.md already advertised this lookup; this
brings the implementation in line with the documented contract.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

README.md

@@ -335,7 +335,7 @@ Legacy aliases `deepseek-chat` / `deepseek-reasoner` map to `deepseek-v4-flash`.
 
 ## Publishing Your Own Skill
 
-DeepSeek TUI discovers skills from workspace directories (`.agents/skills` → `skills` → `.opencode/skills` → `.claude/skills` → `.cursor/skills`) and global directories (`~/.agents/skills` → `~/.deepseek/skills`). Each skill is a directory with a `SKILL.md` file:
+DeepSeek TUI discovers skills from workspace directories (`.agents/skills` → `skills` → `.opencode/skills` → `.claude/skills` → `.cursor/skills`) and global directories (`~/.agents/skills` → `~/.claude/skills` → `~/.deepseek/skills`). Each skill is a directory with a `SKILL.md` file:
 
 ```text
 ~/.agents/skills/my-skill/

crates/tui/src/skills/mod.rs

@@ -42,6 +42,16 @@ pub fn agents_global_skills_dir() -> Option<PathBuf> {
     dirs::home_dir().map(|p| p.join(".agents").join("skills"))
 }
 
+/// Global Claude-compatible skills directory (`~/.claude/skills`). The
+/// SKILL.md frontmatter convention is shared across the broader Claude
+/// ecosystem, so picking up the global path lets users inherit skills
+/// they already installed for other Claude-compatible tools without
+/// re-authoring them in DeepSeek's native layout (#902).
+#[must_use]
+pub fn claude_global_skills_dir() -> Option<PathBuf> {
+    dirs::home_dir().map(|p| p.join(".claude").join("skills"))
+}
+
 // === Types ===
 
 /// Parsed representation of a SKILL.md definition.
@@ -334,7 +344,8 @@ pub fn resolve_skills_dir(workspace: &Path) -> PathBuf {
 /// 4. `<workspace>/.claude/skills` — Claude Code interop.
 /// 5. `<workspace>/.cursor/skills` — Cursor interop.
 /// 6. [`agents_global_skills_dir`] — agentskills.io global.
-/// 7. [`default_skills_dir`] — DeepSeek global, user-installed.
+/// 7. [`claude_global_skills_dir`] — Claude-ecosystem global (#902).
+/// 8. [`default_skills_dir`] — DeepSeek global, user-installed.
 ///
 /// Only directories that exist on disk are returned — callers don't
 /// need to filter further. Returns an empty vec when nothing is
@@ -351,6 +362,9 @@ pub fn skills_directories(workspace: &Path) -> Vec<PathBuf> {
     if let Some(global_agents) = agents_global_skills_dir() {
         candidates.push(global_agents);
     }
+    if let Some(global_claude) = claude_global_skills_dir() {
+        candidates.push(global_claude);
+    }
     candidates.push(default_skills_dir());
     existing_skill_dirs(candidates)
 }
@@ -742,6 +756,38 @@ mod tests {
         );
     }
 
+    #[test]
+    fn claude_global_skills_dir_returns_home_relative_path() {
+        // Smoke test for the #902 helper. We don't assert the exact path
+        // because dirs::home_dir() is host-dependent; we just pin the
+        // suffix shape so a future refactor can't silently rename it.
+        let path = super::claude_global_skills_dir().expect("home dir resolves on test host");
+        assert!(path.ends_with(".claude/skills") || path.ends_with(r".claude\skills"));
+    }
+
+    #[test]
+    fn existing_skill_dirs_orders_globals_agents_then_claude_then_deepseek() {
+        // Pins the precedence among the three global skill roots (#902).
+        // Workspace candidates are tested separately above; here we only
+        // exercise the global ordering at the existing_skill_dirs level
+        // so the assertion is host-independent.
+        let tmpdir = TempDir::new().unwrap();
+        let agents_global = tmpdir.path().join(".agents").join("skills");
+        let claude_global = tmpdir.path().join(".claude").join("skills");
+        let deepseek_global = tmpdir.path().join(".deepseek").join("skills");
+        std::fs::create_dir_all(&agents_global).unwrap();
+        std::fs::create_dir_all(&claude_global).unwrap();
+        std::fs::create_dir_all(&deepseek_global).unwrap();
+
+        let dirs = super::existing_skill_dirs(vec![
+            agents_global.clone(),
+            claude_global.clone(),
+            deepseek_global.clone(),
+        ]);
+
+        assert_eq!(dirs, vec![agents_global, claude_global, deepseek_global]);
+    }
+
     #[test]
     fn existing_skill_dirs_keeps_agents_global_before_deepseek_global() {
         let tmpdir = TempDir::new().unwrap();

docs/CONFIGURATION.md

@@ -326,7 +326,7 @@ If you are upgrading from older releases:
   keys such as `worker`, `explorer`, `general`, `explore`, `plan`, and
   `review`. Values must normalize to a supported DeepSeek model id before an
   agent is spawned.
-- `skills_dir` (string, optional): defaults to `~/.deepseek/skills` (each skill is a directory containing `SKILL.md`). Workspace-local `.agents/skills` or `./skills` are preferred when present; the runtime also discovers global agentskills.io-compatible `~/.agents/skills`.
+- `skills_dir` (string, optional): defaults to `~/.deepseek/skills` (each skill is a directory containing `SKILL.md`). Workspace-local `.agents/skills` or `./skills` are preferred when present; the runtime also discovers global agentskills.io-compatible `~/.agents/skills` and the broader Claude-ecosystem `~/.claude/skills`.
 - `mcp_config_path` (string, optional): defaults to `~/.deepseek/mcp.json`.
   It is visible in `/config` and can be changed from the TUI. The new path is
   used immediately by `/mcp`, but rebuilding the model-visible MCP tool pool