chore: add rustfmt and clippy configuration files

- Add .rustfmt.toml with stable-only features
- Add clippy.toml to match CI settings
- Update code formatting to match new configuration

Author: Test User

.rustfmt.toml

@@ -0,0 +1,13 @@
+max_width = 100
+hard_tabs = false
+tab_spaces = 4
+newline_style = "Auto"
+use_small_heuristics = "Default"
+reorder_imports = true
+reorder_modules = true
+remove_nested_parens = true
+edition = "2021"
+merge_derives = true
+use_field_init_shorthand = true
+use_try_shorthand = true
+force_explicit_abi = true

clippy.toml

@@ -0,0 +1,3 @@
+warn-on-all-wildcard-imports = true
+redundant-pattern-matching-deny = true
+needless-borrows-for-generic-args-deny = true

src/cli/mod.rs

@@ -212,14 +212,9 @@ mod tests {
         }
 
         // Test zsh completion with output
-        let cli = Cli::try_parse_from([
-            "essex",
-            "completion",
-            "zsh",
-            "--output",
-            "/tmp/completions",
-        ])
-        .unwrap();
+        let cli =
+            Cli::try_parse_from(["essex", "completion", "zsh", "--output", "/tmp/completions"])
+                .unwrap();
         match cli.command {
             Commands::Completion { shell, output } => {
                 assert!(matches!(shell, Shell::Zsh));
@@ -245,14 +240,9 @@ mod tests {
         let completion_dir = temp_dir.path().join("completions");
         fs::create_dir(&completion_dir)?;
 
-        let cli = Cli::try_parse_from([
-            "essex",
-            "completion",
-            "zsh",
-            "--output",
-            "/tmp/completions",
-        ])
-        .unwrap();
+        let cli =
+            Cli::try_parse_from(["essex", "completion", "zsh", "--output", "/tmp/completions"])
+                .unwrap();
         assert!(cli.execute().is_ok());
 
         Ok(())