feat(PROJ-44): Snippet + match_field fuer Suche, GetAttachmentText

Hit-Struct um Snippet + MatchField erweitert. enrichHitsWithSnippets
fuellt diese pro Treffer: detectMatchField probt subject>body>
attachment_text>attachment_names>from_addr>to_addr; buildSnippet ruft
CALL SNIPPETS mit <b>-Markern. Snippet-Fehler droppen den Treffer nicht.

AttachmentTextReader-Interface + Manticore-Implementation
GetAttachmentText liefert den indexierten OCR-Text fuer den neuen
/ocr-text-Endpoint.

internal/index/manticore.go

@@ -226,6 +226,28 @@ func (idx *manticoreIndex) UpdateAttachmentText(mailID, text string) error {
 	return nil
 }
 
+// GetAttachmentText returns the stored OCR-extracted text for a mail or
+// "" if the document is not (yet) indexed or has no attachment text.
+// Implements index.AttachmentTextReader (PROJ-44).
+//
+// Errors are returned only for unexpected SQL failures — a missing row maps
+// to ("", nil) so callers can treat it the same as "no OCR text available".
+func (idx *manticoreIndex) GetAttachmentText(mailID string) (string, error) {
+	rowID := hashMailID(mailID)
+	var text string
+	err := idx.db.QueryRow(
+		fmt.Sprintf(`SELECT attachment_text FROM %s WHERE id = ? LIMIT 1`, idx.table),
+		rowID,
+	).Scan(&text)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			return "", nil
+		}
+		return "", fmt.Errorf("manticore GetAttachmentText %s: %w", idx.table, err)
+	}
+	return text, nil
+}
+
 // Delete removes a document by mail ID hash.
 func (idx *manticoreIndex) Delete(id string) error {
 	rowID := hashMailID(id)
@@ -357,6 +379,14 @@ func (idx *manticoreIndex) Search(req SearchRequest) (*SearchResult, error) {
 		return nil, fmt.Errorf("manticore Search rows: %w", err)
 	}
 
+	// PROJ-44: per-hit snippet + match_field heuristic. Only meaningful when
+	// the caller supplied a full-text query. Failures are logged via the
+	// returned error message wrapping but do not drop the hit — see
+	// enrichHitsWithSnippets.
+	if req.Query != "" && len(hits) > 0 {
+		idx.enrichHitsWithSnippets(hits, req.Query)
+	}
+
 	return &SearchResult{Total: total, Hits: hits}, nil
 }