chore: align codebase with bible engineering contracts

- identifier-normalization: use strings.EqualFold in h3c/parser.go
- import-export: CSV now uses UTF-8 BOM and semicolon delimiter
- go-code-style: translate all Russian source strings to English (ADL-007)
- go-background-tasks: add Type, Message, Result fields to Job struct
- go-api: wrap list endpoints in {items, total_count, page, per_page, total_pages}
- module-structure: rename helpers.go → context_sleep.go
- build-version-display: htmlError renders version footer on error pages
- go-logging: migrate all log.Printf calls to log/slog with structured attrs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/exporter/exporter.go

@@ -21,7 +21,11 @@ func New(result *models.AnalysisResult) *Exporter {
 
 // ExportCSV exports serial numbers to CSV format
 func (e *Exporter) ExportCSV(w io.Writer) error {
+	if _, err := w.Write([]byte{0xEF, 0xBB, 0xBF}); err != nil {
+		return err
+	}
 	writer := csv.NewWriter(w)
+	writer.Comma = ';'
 	defer writer.Flush()
 
 	// Header