style: Apply rustfmt with stable-only config

- Fixed rustfmt.toml to only use stable options (removed nightly-only)
- Applied cargo fmt --all to fix formatting violations
- Stable options: edition=2021, max_width=100, reorder_imports/modules, match_block_trailing_comma

rustfmt.toml

@@ -1,5 +1,6 @@
 # Linux Patch Manager - Rust Formatting Configuration
 # Run: cargo fmt --check (CI) or cargo fmt (fix)
+# Only stable options - nightly-only options removed
 
 edition = "2021"
 max_width = 100
@@ -10,15 +11,4 @@ use_small_heuristics = "Default"
 reorder_imports = true
 reorder_modules = true
 remove_nested_parens = true
-fn_single_line = false
-where_single_line = false
-imports_granularity = "Crate"
-group_imports = "StdExternalCrate"
-normalize_doc_attributes = true
-wrap_comments = true
-comment_width = 80
-indent_style = "Block"
-trailing_comma = "Vertical"
 match_block_trailing_comma = true
-blank_lines_lower_bound = 0
-blank_lines_upper_bound = 1