chore: cargo fmt + drop needless borrow flagged by clippy

CI on PR #256 flagged two minor lint hits in the privacy lane:
- skills/mod.rs: rustfmt wanted the new regression test's
  `let rendered = …` line collapsed to one chain.
- main.rs:1614: `selected_skills_dir` is already `&PathBuf`, so
  passing `&selected_skills_dir` is a `&&PathBuf` and clippy's
  `needless_borrow` triggers under `-D warnings`.

No behavior change; same coverage and outputs. Re-runs locally:
  cargo fmt --all -- --check  → clean
  cargo clippy --workspace --all-targets --all-features --locked -- -D warnings → clean

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/tui/src/main.rs

@@ -1611,7 +1611,7 @@ async fn run_doctor(config: &Config, workspace: &Path, config_path_override: Opt
     println!(
         "  {} selected skills dir: {}",
         "·".dimmed(),
-        crate::utils::display_path(&selected_skills_dir)
+        crate::utils::display_path(selected_skills_dir)
     );
     if !agents_skills_dir.exists() && !local_skills_dir.exists() && !global_skills_dir.exists() {
         println!("    Run `deepseek setup --skills` (or add --local for ./skills).");

crates/tui/src/skills/mod.rs

@@ -364,10 +364,9 @@ mod tests {
             "---\nname: friendly-name\ndescription: drift case\n---\nbody",
         );
 
-        let rendered = crate::skills::render_available_skills_context(
-            &tmpdir.path().join("skills"),
-        )
-        .expect("skill context");
+        let rendered =
+            crate::skills::render_available_skills_context(&tmpdir.path().join("skills"))
+                .expect("skill context");
 
         let real_path = tmpdir
             .path()