feat: log loaded pattern files for debugging

When patterns-repo is configured, now logs at Info level:
- File paths loaded from each repo
- Count of files per repo

At Debug level logs skipped files (non-markdown/txt/yaml).

Warns if no pattern files were loaded from a repo (likely
misconfigured patterns-files path).

Closes #64

cmd/review-bot/main.go

@@ -544,6 +544,9 @@ func fetchPatterns(ctx context.Context, client *gitea.Client, patternsRepo, patt
 		}
 		owner, repo := parts[0], parts[1]
 
+		var repoLoadedFiles []string
+		var repoSkippedFiles []string
+
 		for _, path := range paths {
 			path = strings.TrimSpace(path)
 			if path == "" {
@@ -559,11 +562,22 @@ func fetchPatterns(ctx context.Context, client *gitea.Client, patternsRepo, patt
 			for filePath, content := range files {
 				// Only include markdown and text files as patterns
 				if !isPatternFile(filePath) {
+					repoSkippedFiles = append(repoSkippedFiles, filePath)
 					continue
 				}
+				repoLoadedFiles = append(repoLoadedFiles, filePath)
 				sb.WriteString(fmt.Sprintf("### %s/%s\n\n%s\n\n", repoRef, filePath, content))
 			}
 		}
+
+		if len(repoLoadedFiles) > 0 {
+			slog.Info("loaded pattern files", "repo", repoRef, "count", len(repoLoadedFiles), "files", repoLoadedFiles)
+		} else {
+			slog.Warn("no pattern files loaded", "repo", repoRef, "paths", paths)
+		}
+		if len(repoSkippedFiles) > 0 {
+			slog.Debug("skipped non-pattern files", "repo", repoRef, "count", len(repoSkippedFiles), "files", repoSkippedFiles)
+		}
 	}
 	return sb.String()
 }