PDF: enlarge header logo and center attendees column (Task #364)

- Increased logoBoxSize multiplier from 1.8 to 2.8 so the header logo
  renders noticeably larger in the PDF output.
- Changed attendees column text alignment from direction-based (right for
  RTL) to "center" so attendee names are centered in their column.
- Both AR and EN PDFs verified: valid PDF output, logo embedded, correct
  alignment. Code review PASSED, e2e tests PASSED.

artifacts/api-server/src/lib/pdf-renderer.ts

@@ -605,7 +605,7 @@ export async function renderSchedulePdf(input: RenderPdfInput): Promise<Buffer>
   const headerLeftEdge = doc.page.margins.left;
   const headerWidth = doc.page.width - doc.page.margins.left - doc.page.margins.right;
   const headerTopY = doc.y;
-  const logoBoxSize = titleSize * 1.8;
+  const logoBoxSize = titleSize * 2.8;
   let titleX = headerLeftEdge;
   let titleWidth = headerWidth;
   if (input.logo && input.logo.length > 0) {
@@ -802,7 +802,7 @@ export async function renderSchedulePdf(input: RenderPdfInput): Promise<Buffer>
                 }
                 return parts.join("\n");
               })(),
-        align: alignment(input.font, isRtl),
+        align: "center",
       },
       {
         text: formatTimeRange(meeting.startTime, meeting.endTime, input.lang),