feat: resolve old inline comments when superseding review

Closes #27

After superseding an old review, resolves all its inline comments via
POST /pulls/comments/{id}/resolve. This clears unresolved conversation
markers from the PR timeline and diff view.

New API methods:
- ListReviewComments: paginated GET /repos/.../pulls/{n}/reviews/{id}/comments
- ResolveComment: POST /repos/.../pulls/comments/{id}/resolve

Behavior:
- Only resolves after successful supersede (gated on supersedeOK)
- Aggregates failures and logs at warn level
- Truncates error bodies to 256 bytes (security)
- Non-fatal: review still posts even if resolution fails

gitea/client.go

@@ -82,6 +82,7 @@ type ChangedFile struct {
 
 // ReviewComment represents an inline comment to attach to a review.
 type ReviewComment struct {
+	ID          int64  `json:"id,omitempty"`
 	Path        string `json:"path"`
 	NewPosition int64  `json:"new_position"`
 	Body        string `json:"body"`
@@ -513,3 +514,60 @@ func (c *Client) RequestReviewer(ctx context.Context, owner, repo string, number
 	}
 	return nil
 }
+
+// ListReviewComments returns the inline comments attached to a specific review.
+// Paginates through all pages.
+func (c *Client) ListReviewComments(ctx context.Context, owner, repo string, prNumber int, reviewID int64) ([]ReviewComment, error) {
+	const pageSize = 50
+	var all []ReviewComment
+	for page := 1; ; page++ {
+		reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/%d/reviews/%d/comments?limit=%d&page=%d",
+			c.baseURL,
+			url.PathEscape(owner),
+			url.PathEscape(repo),
+			prNumber,
+			reviewID,
+			pageSize,
+			page)
+		body, err := c.doGet(ctx, reqURL)
+		if err != nil {
+			return nil, fmt.Errorf("list review comments (page %d): %w", page, err)
+		}
+		var batch []ReviewComment
+		if err := json.Unmarshal(body, &batch); err != nil {
+			return nil, fmt.Errorf("parse review comments (page %d): %w", page, err)
+		}
+		all = append(all, batch...)
+		if len(batch) < pageSize {
+			break
+		}
+	}
+	return all, nil
+}
+
+// ResolveComment marks an inline review comment as resolved.
+func (c *Client) ResolveComment(ctx context.Context, owner, repo string, commentID int64) error {
+	reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/comments/%d/resolve",
+		c.baseURL,
+		url.PathEscape(owner),
+		url.PathEscape(repo),
+		commentID)
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, reqURL, nil)
+	if err != nil {
+		return fmt.Errorf("create resolve request: %w", err)
+	}
+	req.Header.Set("Authorization", "token "+c.token)
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return fmt.Errorf("resolve comment: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusCreated && resp.StatusCode != http.StatusNoContent {
+		body, _ := io.ReadAll(io.LimitReader(resp.Body, 256))
+		return fmt.Errorf("resolve comment failed (status %d): %s", resp.StatusCode, body)
+	}
+	return nil
+}