fix: quick wins (#7, #9, #13)

- Add --version flag and log version on startup (closes #9)
- URL-escape ref query parameter in GetFileContentRef (closes #7)
- Add go vet to release workflow (closes #13)

Renamed local url variable to reqURL to avoid shadowing net/url package.

gitea/client.go

@@ -8,6 +8,7 @@ import (
 	"io"
 	"log"
 	"net/http"
+	"net/url"
 	"strings"
 	"time"
 )
@@ -117,8 +118,8 @@ func (c *Client) GetFileContent(ctx context.Context, owner, repo, filepath strin
 
 // GetFileContentRef fetches a file from a specific ref (branch/tag/sha) in a repo.
 func (c *Client) GetFileContentRef(ctx context.Context, owner, repo, filepath, ref string) (string, error) {
-	url := fmt.Sprintf("%s/api/v1/repos/%s/%s/raw/%s?ref=%s", c.baseURL, owner, repo, filepath, ref)
-	body, err := c.doGet(ctx, url)
+	reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/raw/%s?ref=%s", c.baseURL, owner, repo, filepath, url.QueryEscape(ref))
+	body, err := c.doGet(ctx, reqURL)
 	if err != nil {
 		return "", fmt.Errorf("fetch file %s@%s: %w", filepath, ref, err)
 	}