sync file-type support across upload/convert and fix collected_at timezone handling

internal/parser/parser.go

@@ -66,11 +66,41 @@ func (p *BMCParser) parseFiles() error {
 	result.Filename = p.result.Filename
 
 	appendExtractionWarnings(result, p.files)
+	if result.CollectedAt.IsZero() {
+		if ts := inferCollectedAtFromExtractedFiles(p.files); !ts.IsZero() {
+			result.CollectedAt = ts.UTC()
+		}
+	}
 	p.result = result
 
 	return nil
 }
 
+func inferCollectedAtFromExtractedFiles(files []ExtractedFile) time.Time {
+	var latestReliable time.Time
+	var latestAny time.Time
+	for _, f := range files {
+		ts := f.ModTime
+		if ts.IsZero() {
+			continue
+		}
+		if latestAny.IsZero() || ts.After(latestAny) {
+			latestAny = ts
+		}
+		// Ignore placeholder archive mtimes like 1980-01-01.
+		if ts.Year() < 2000 {
+			continue
+		}
+		if latestReliable.IsZero() || ts.After(latestReliable) {
+			latestReliable = ts
+		}
+	}
+	if !latestReliable.IsZero() {
+		return latestReliable
+	}
+	return latestAny
+}
+
 func appendExtractionWarnings(result *models.AnalysisResult, files []ExtractedFile) {
 	if result == nil {
 		return