feat: add CLI update check with npm registry indicator

On app start, check the npm registry for the latest
@anthropic-ai/claude-code version and compare against the installed
version. If behind, the CLI badge turns amber with a pulsing up-arrow
and a tooltip advising how to update.

Also bumps SUPPORTED_CLI_VERSION to 2.1.72.

src-tauri/src/commands.rs

@@ -662,6 +662,37 @@ pub async fn fetch_changelog() -> Result<Vec<ChangelogEntry>, String> {
         .collect())
 }
 
+fn parse_npm_cli_version(json: &str) -> Result<String, String> {
+    let data: serde_json::Value =
+        serde_json::from_str(json).map_err(|e| format!("Failed to parse response: {}", e))?;
+    data.get("version")
+        .and_then(|v| v.as_str())
+        .map(|s| s.to_string())
+        .ok_or_else(|| "No version field in response".to_string())
+}
+
+#[tauri::command]
+pub async fn check_cli_latest_version() -> Result<String, String> {
+    let client = reqwest::Client::new();
+    let response = client
+        .get("https://registry.npmjs.org/@anthropic-ai/claude-code/latest")
+        .header("Accept", "application/json")
+        .send()
+        .await
+        .map_err(|e| format!("Failed to fetch CLI version: {}", e))?;
+
+    if !response.status().is_success() {
+        return Err(format!("Registry returned status: {}", response.status()));
+    }
+
+    let body = response
+        .text()
+        .await
+        .map_err(|e| format!("Failed to read response: {}", e))?;
+
+    parse_npm_cli_version(&body)
+}
+
 #[derive(Debug, Clone, serde::Serialize)]
 pub struct SavedFileInfo {
     pub path: String,
@@ -2838,6 +2869,35 @@ mod tests {
         assert!(json.contains("null") || json.contains("release_notes"));
     }
 
+    // ==================== parse_npm_cli_version tests ====================
+
+    #[test]
+    fn test_parse_npm_cli_version_valid() {
+        let json = r#"{"name":"@anthropic-ai/claude-code","version":"2.1.72","description":"Claude Code"}"#;
+        let result = parse_npm_cli_version(json).unwrap();
+        assert_eq!(result, "2.1.72");
+    }
+
+    #[test]
+    fn test_parse_npm_cli_version_missing_field() {
+        let json = r#"{"name":"@anthropic-ai/claude-code","description":"no version here"}"#;
+        let result = parse_npm_cli_version(json);
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_parse_npm_cli_version_invalid_json() {
+        let result = parse_npm_cli_version("not json at all");
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_parse_npm_cli_version_non_string_version() {
+        let json = r#"{"version":123}"#;
+        let result = parse_npm_cli_version(json);
+        assert!(result.is_err());
+    }
+
     // ==================== SavedFileInfo struct tests ====================
 
     #[test]

src-tauri/src/lib.rs

@@ -134,6 +134,7 @@ pub fn run() {
             list_skills,
             check_for_updates,
             fetch_changelog,
+            check_cli_latest_version,
             save_temp_file,
             register_temp_file,
             get_temp_files,