fix: track skill directory name for name/dir mismatch detection

Adds dir_name field to SkillSummary to enable detection of skills where
the SKILL.md frontmatter name differs from the parent directory name.
Also adds SkillMetadataDrift struct for tracking mismatches (used by
skills JSON output in follow-up).

Generated with https://github.com/Yeachan-Heo/gajae-code
Co-authored-by: Gajae Code <dev@gajae-code.com>

rust/crates/commands/src/lib.rs

@@ -2181,6 +2181,16 @@ struct SkillSummary {
     origin: SkillOrigin,
     // #729: on-disk path parity with AgentSummary
     path: Option<PathBuf>,
+    // #445: directory name for detecting name/dir mismatch
+    dir_name: Option<String>,
+}
+
+/// A skill where the frontmatter name differs from the directory name.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub(crate) struct SkillMetadataDrift {
+    pub(crate) dir_name: String,
+    pub(crate) frontmatter_name: String,
+    pub(crate) path: PathBuf,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -4035,15 +4045,16 @@ fn load_skills_from_roots(roots: &[SkillRoot]) -> std::io::Result<Vec<SkillSumma
                         continue;
                     }
                     let contents = fs::read_to_string(skill_path)?;
+                    let dir_name = entry.file_name().to_string_lossy().to_string();
                     let (name, description) = parse_skill_frontmatter(&contents);
                     root_skills.push(SkillSummary {
-                        name: name
-                            .unwrap_or_else(|| entry.file_name().to_string_lossy().to_string()),
+                        name: name.unwrap_or_else(|| dir_name.clone()),
                         description,
                         source: root.source,
                         shadowed_by: None,
                         origin: root.origin,
                         path: Some(entry.path()),
+                        dir_name: Some(dir_name),
                     });
                 }
                 SkillOrigin::LegacyCommandsDir => {
@@ -4076,6 +4087,7 @@ fn load_skills_from_roots(roots: &[SkillRoot]) -> std::io::Result<Vec<SkillSumma
                         shadowed_by: None,
                         origin: root.origin,
                         path: Some(markdown_path),
+                        dir_name: None,
                     });
                 }
             }