fix: address review feedback on PR #93

- Fix Retry-After slice mutation: copy c.RetryBackoff before modifying
  to prevent permanent mutation of the shared slice (sonnet#1, security#1)
- Cap Retry-After to 120s maximum to prevent excessive sleeps (security#2)
- Guard auth header: only set Authorization when token is non-empty (gpt#2)
- Fix GetFileContent doc comment to match actual behavior (sonnet#3, gpt#1)
- Remove dead 'in_progress/queued' case in mapCheckRunStatus (sonnet#4)
- Add testing.Short() guard to slow retry test (sonnet#5)
- Reject dot-segments in escapePath to prevent path traversal (security#3)
- Add regression tests for non-mutation and escapePath safety

github/client.go

@@ -93,11 +93,16 @@ func (c *Client) SetHTTPClient(hc *http.Client) {
 }
 
 // doRequest performs an HTTP request with retry on 429 rate limit responses.
-// It respects the Retry-After header when present.
+// It respects the Retry-After header when present (capped at maxRetryAfter).
 func (c *Client) doRequest(ctx context.Context, method, url string, accept string) ([]byte, error) {
 	const maxAttempts = 3
-	backoff := c.RetryBackoff
-	if backoff == nil {
+	const maxRetryAfter = 120 * time.Second
+
+	var backoff []time.Duration
+	if c.RetryBackoff != nil {
+		backoff = make([]time.Duration, len(c.RetryBackoff))
+		copy(backoff, c.RetryBackoff)
+	} else {
 		backoff = []time.Duration{1 * time.Second, 2 * time.Second}
 	}
 
@@ -125,7 +130,9 @@ func (c *Client) doRequest(ctx context.Context, method, url string, accept strin
 		if err != nil {
 			return nil, fmt.Errorf("create request: %w", err)
 		}
-		req.Header.Set("Authorization", "Bearer "+c.token)
+		if c.token != "" {
+			req.Header.Set("Authorization", "Bearer "+c.token)
+		}
 		if accept != "" {
 			req.Header.Set("Accept", accept)
 		} else {
@@ -156,8 +163,12 @@ func (c *Client) doRequest(ctx context.Context, method, url string, accept strin
 			// Check for Retry-After header and override backoff if present
 			if ra := resp.Header.Get("Retry-After"); ra != "" {
 				if seconds, err := strconv.Atoi(ra); err == nil && seconds > 0 {
+					delay := time.Duration(seconds) * time.Second
+					if delay > maxRetryAfter {
+						delay = maxRetryAfter
+					}
 					if attempt < len(backoff) {
-						backoff[attempt] = time.Duration(seconds) * time.Second
+						backoff[attempt] = delay
 					}
 				}
 			}