feat: convert DOCX to PDF on-the-fly for inline viewing

DOCX/DOC documents are now converted to PDF using LibreOffice headless
when the user clicks "Otwórz". The converted PDF is cached next to the
original file so subsequent views are instant.

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

blueprints/board/routes.py

@@ -22,6 +22,8 @@ Endpoints - Documents:
 """
 
 import os
+import subprocess
+import tempfile
 from datetime import datetime
 from flask import (
     render_template, request, redirect, url_for, flash,
@@ -537,7 +539,7 @@ def document_download(doc_id):
 @login_required
 @rada_member_required
 def document_view(doc_id):
-    """Open a PDF document inline in the browser"""
+    """Open a document inline in the browser (converts DOCX to PDF on the fly)"""
     db = SessionLocal()
     try:
         doc = db.query(BoardDocument).filter(
@@ -558,6 +560,34 @@ def document_view(doc_id):
             flash('Plik dokumentu nie został znaleziony na serwerze.', 'error')
             return redirect(url_for('board.meeting_view', meeting_id=doc.meeting_id))
 
+        # DOCX/DOC: convert to PDF for inline viewing
+        if doc.file_extension in ('docx', 'doc'):
+            pdf_path = file_path.rsplit('.', 1)[0] + '.pdf'
+
+            # Convert only if cached PDF doesn't exist
+            if not os.path.exists(pdf_path):
+                try:
+                    result = subprocess.run(
+                        ['libreoffice', '--headless', '--convert-to', 'pdf',
+                         '--outdir', os.path.dirname(file_path), file_path],
+                        capture_output=True, timeout=30
+                    )
+                    if result.returncode != 0:
+                        current_app.logger.error(f"DOCX to PDF conversion failed: {result.stderr.decode()}")
+                        flash('Nie udało się przekonwertować dokumentu do PDF.', 'error')
+                        return redirect(url_for('board.meeting_view', meeting_id=doc.meeting_id))
+                except subprocess.TimeoutExpired:
+                    flash('Konwersja dokumentu trwała za długo.', 'error')
+                    return redirect(url_for('board.meeting_view', meeting_id=doc.meeting_id))
+
+            pdf_name = doc.original_filename.rsplit('.', 1)[0] + '.pdf'
+            return send_file(
+                pdf_path,
+                mimetype='application/pdf',
+                as_attachment=False,
+                download_name=pdf_name
+            )
+
         return send_file(
             file_path,
             mimetype=doc.mime_type,