[gobby-cli-#122] fix(gsqz): Use sort_by_key for clippy 1.95 unnecessary_sort_by

Two pre-existing call sites in crates/gsqz/src/primitives/group.rs
trigger Rust 1.95.0's new clippy::unnecessary_sort_by lint. Local
toolchain is 1.94 so they slipped through; CI runs 1.95 and rejects
them. Mechanical replacement of

    sort_by(|a, b| b.1.len().cmp(&a.1.len()))

with

    sort_by_key(|b| std::cmp::Reverse(b.1.len()))

at lines 373 and 414. No behavior change. Rolls into the unreleased
gsqz 0.4.1 -- no version bump, no CHANGELOG entry (this is a CI
correctness fix, not a user-facing change).

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

Author: joshwilhelmi

crates/gsqz/src/primitives/group.rs

@@ -370,7 +370,7 @@ fn group_by_extension(lines: Vec<String>) -> Vec<String> {
 
     // Sort by count descending
     let mut sorted: Vec<_> = groups.into_iter().collect();
-    sorted.sort_by(|a, b| b.1.len().cmp(&a.1.len()));
+    sorted.sort_by_key(|b| std::cmp::Reverse(b.1.len()));
 
     let mut result = Vec::new();
     for (ext, files) in &sorted {
@@ -411,7 +411,7 @@ fn group_by_directory(lines: Vec<String>) -> Vec<String> {
     }
 
     let mut sorted: Vec<_> = groups.into_iter().collect();
-    sorted.sort_by(|a, b| b.1.len().cmp(&a.1.len()));
+    sorted.sort_by_key(|b| std::cmp::Reverse(b.1.len()));
 
     let mut result = Vec::new();
     for (dirname, files) in &sorted {