Retry Reddit edge blocks instead of skipping events

Reddit's edge can return temporary HTML 403s. Beyond 404/410, a 4xx is now
only permanent when the Matrix server returns an errcode, and reaction
images only fall back to text on 404/410.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: Fizzadar

pkg/connector/emoji.go

@@ -45,7 +45,7 @@ var reactionHTTPClient = &http.Client{
 	Timeout: 30 * time.Second,
 	CheckRedirect: func(req *http.Request, via []*http.Request) error {
 		if len(via) >= 3 || req.URL.Scheme != "https" || req.URL.Host != "i.redd.it" {
-			return unbridgeable(errors.New("unexpected reaction image redirect"))
+			return errors.New("unexpected reaction image redirect")
 		}
 		return nil
 	},
@@ -72,7 +72,7 @@ func (r *RedditClient) reactionImage(ctx context.Context, key string) (string, s
 		defer resp.Body.Close()
 		if resp.StatusCode != http.StatusOK {
 			err = fmt.Errorf("reddit reaction image is unavailable (HTTP %d)", resp.StatusCode)
-			if isPermanentStatus(resp.StatusCode) {
+			if isGoneStatus(resp.StatusCode) {
 				err = unbridgeable(err)
 			}
 			return "", "", err

pkg/connector/media.go

@@ -47,7 +47,7 @@ func mediaError(ctx context.Context, operation string, err error) error {
 	if errors.As(err, &httpErr) && httpErr.Response != nil {
 		safe = fmt.Errorf("%s failed (HTTP %d)", operation, httpErr.Response.StatusCode)
 	}
-	if isUnbridgeable(err) || isPermanentHTTPError(err) {
+	if isPermanentHTTPError(err) {
 		return unbridgeable(safe)
 	}
 	return safe

pkg/connector/unbridgeable.go

@@ -29,12 +29,20 @@ func isUnbridgeable(err error) bool {
 }
 
 // The server refused this specific request, so repeating it cannot succeed.
-// Expired sessions, timeouts and rate limits are retried.
+// Beyond not-found, require a Matrix errcode: Reddit's edge also returns
+// temporary HTML blocks. Expired sessions, timeouts and rate limits retry.
 func isPermanentHTTPError(err error) bool {
 	var httpErr mautrix.HTTPError
-	return errors.As(err, &httpErr) && httpErr.Response != nil && !isUnauthorized(err) && isPermanentStatus(httpErr.Response.StatusCode)
+	if !errors.As(err, &httpErr) || httpErr.Response == nil || isUnauthorized(err) {
+		return false
+	}
+	code := httpErr.Response.StatusCode
+	if isGoneStatus(code) {
+		return true
+	}
+	return httpErr.RespError != nil && code >= 400 && code < 500 && code != http.StatusRequestTimeout && code != http.StatusTooManyRequests
 }
 
-func isPermanentStatus(code int) bool {
-	return code >= 400 && code < 500 && code != http.StatusUnauthorized && code != http.StatusRequestTimeout && code != http.StatusTooManyRequests
+func isGoneStatus(code int) bool {
+	return code == http.StatusNotFound || code == http.StatusGone
 }