chore: add golangci-lint v2 config and fix linter warnings (#46)

- [x] Add golangci-lint v2 configuration with formatters section
- [x] Reorganize linters-settings under linters section
- [x] Replace if-else chains with switch statements for clarity
- [x] Wrap all ignored error returns with `_ = ` pattern
- [x] Add OSC 8 hyperlink helper function for clickable ports
- [x] Add blank line in table styling function
- [x] Remove unnecessary type assertion in test

internal/version/checker.go

@@ -101,7 +101,7 @@ func (c *Checker) fetchLatestRelease(ctx context.Context) (*ReleaseInfo, error)
 	if err != nil {
 		return nil, err
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode != http.StatusOK {
 		return nil, fmt.Errorf("GitHub API returned status %d", resp.StatusCode)