fix(npm): remove extra quotes in code action version replacements (#29)

* fix(npm): remove extra quotes in code action version replacements

When applying code actions to update package.json versions, the
formatter was adding quotes around version strings. However, the
parser's version_range already excludes quotes (it spans only the
version text itself, not the surrounding JSON quotes).

This caused double-quoting:
  Before: "typescript": "5.0.0"
  After:  "typescript": ""6.0.0""  (WRONG)

Root cause: NpmFormatter.format_version_for_code_action was adding
quotes that already exist in the JSON structure.

Fix: Return version string without quotes. The TextEdit replaces
only the version content (not the quotes), so no additional quotes
should be added.

Cargo ecosystem is unaffected - toml_edit spans include quotes, so
CargoFormatter correctly adds quotes when replacing the full span.

* style: fix formatting in npm formatter tests

Author: bug-ops

crates/deps-npm/src/formatter.rs

@@ -4,7 +4,8 @@ pub struct NpmFormatter;
 
 impl EcosystemFormatter for NpmFormatter {
     fn format_version_for_code_action(&self, version: &str) -> String {
-        format!("\"{}\"", version)
+        // Don't add quotes - version_range already excludes them from parser
+        version.to_string()
     }
 
     fn package_url(&self, name: &str) -> String {
@@ -41,14 +42,12 @@ mod tests {
     #[test]
     fn test_format_version() {
         let formatter = NpmFormatter;
+        // Version should not include quotes - parser's version_range excludes them
         assert_eq!(
             formatter.format_version_for_code_action("1.0.214"),
-            "\"1.0.214\""
-        );
-        assert_eq!(
-            formatter.format_version_for_code_action("18.3.1"),
-            "\"18.3.1\""
+            "1.0.214"
         );
+        assert_eq!(formatter.format_version_for_code_action("18.3.1"), "18.3.1");
     }
 
     #[test]