fix: supersede ALL old reviews, not just the most recent

Previously findOwnReview returned only the single most-recent matching
review, so on PRs with multiple force-pushes only the latest old review
got superseded. The rest accumulated as unsuperseded stale reviews.

Changes:
- Add findAllOwnReviews() to collect all non-superseded matching reviews
- Loop over all old reviews in the supersede phase
- Add GetTimelineReviewCommentIDForReview() to find comment IDs by
  review ID (fetches review body, matches in timeline by prefix)
- Each old review gets independently superseded and its inline comments
  resolved

The old findOwnReview is kept for backward compat (tested, may be
useful as a utility).

gitea/client.go

@@ -426,6 +426,65 @@ func (c *Client) GetTimelineReviewCommentID(ctx context.Context, owner, repo str
 	return 0, fmt.Errorf("no timeline event found with sentinel")
 }
 
+// GetTimelineReviewCommentIDForReview finds the timeline comment ID for a
+// specific review by matching its body content in the timeline.
+func (c *Client) GetTimelineReviewCommentIDForReview(ctx context.Context, owner, repo string, number int, reviewID int64) (int64, error) {
+	// Use the reviews API to get the review body, then find in timeline
+	reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/%d/reviews/%d",
+		c.baseURL,
+		url.PathEscape(owner),
+		url.PathEscape(repo),
+		number,
+		reviewID)
+	body, err := c.doGet(ctx, reqURL)
+	if err != nil {
+		return 0, fmt.Errorf("get review %d: %w", reviewID, err)
+	}
+	var review struct {
+		Body string `json:"body"`
+	}
+	if err := json.Unmarshal(body, &review); err != nil {
+		return 0, fmt.Errorf("parse review %d: %w", reviewID, err)
+	}
+	if review.Body == "" {
+		return 0, fmt.Errorf("review %d has empty body", reviewID)
+	}
+
+	// Use a prefix for matching (handles minor trailing whitespace differences)
+	matchPrefix := review.Body
+	if len(matchPrefix) > 200 {
+		matchPrefix = matchPrefix[:200]
+	}
+
+	const pageSize = 50
+	for page := 1; ; page++ {
+		timelineURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/issues/%d/timeline?limit=%d&page=%d",
+			c.baseURL,
+			url.PathEscape(owner),
+			url.PathEscape(repo),
+			number,
+			pageSize,
+			page)
+		tlBody, err := c.doGet(ctx, timelineURL)
+		if err != nil {
+			return 0, fmt.Errorf("get timeline (page %d): %w", page, err)
+		}
+		var events []TimelineEvent
+		if err := json.Unmarshal(tlBody, &events); err != nil {
+			return 0, fmt.Errorf("parse timeline (page %d): %w", page, err)
+		}
+		for _, ev := range events {
+			if ev.Type == "review" && strings.HasPrefix(ev.Body, matchPrefix) {
+				return ev.ID, nil
+			}
+		}
+		if len(events) < pageSize {
+			break
+		}
+	}
+	return 0, fmt.Errorf("no timeline event found for review %d", reviewID)
+}
+
 // EditComment updates the body of an issue/review comment.
 func (c *Client) EditComment(ctx context.Context, owner, repo string, commentID int64, newBody string) error {
 	reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/issues/comments/%d",