Task #380: Darken cell borders to match row color in PDF and web UI

When a row has a color (e.g. red), the cell borders now use a darker
shade of the same color instead of the default gray (#d1d5db).

PDF renderer (pdf-html-renderer.ts):
- Added ROW_COLOR_BORDER map with darker shades for each color
- Colored rows now get both background-color and border-color inline
- Non-merged rows: # and meeting cells get bg+border, attendees and
  time cells get border only (preserving partial coloring behavior)
- Merged rows: all cells get bg+border via coloredStyle

Web UI (executive-meetings.tsx):
- Added 'border' field to ROW_COLOR_OPTIONS with matching darker shades
- tintedCellStyle always applies borderColor when rowBorder exists
- Number cell inline style includes borderColor in both rowBg and
  tintBg (current meeting highlight) branches
- Merge cell style includes borderColor in both tint and rowBg branches
- Border color persists even when current-meeting highlight is active

Color mapping:
  red:    fill #fee2e2 → border #fca5a5
  amber:  fill #fef3c7 → border #fcd34d
  green:  fill #dcfce7 → border #86efac
  blue:   fill #dbeafe → border #93c5fd
  violet: fill #ede9fe → border #c4b5fd
  gray:   fill #f3f4f6 → border #d1d5db

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

@@ -22,6 +22,15 @@ const ROW_COLOR_FILL: Record<string, string> = {
   gray: "#f3f4f6",
 };
 
+const ROW_COLOR_BORDER: Record<string, string> = {
+  red: "#fca5a5",
+  amber: "#fcd34d",
+  green: "#86efac",
+  blue: "#93c5fd",
+  violet: "#c4b5fd",
+  gray: "#d1d5db",
+};
+
 function fontsDir(): string {
   const here =
     typeof __dirname === "string"
@@ -196,27 +205,30 @@ function buildMeetingRow(meeting: PdfMeeting, input: RenderPdfInput): string {
   const location = meeting.location ? `<br/><span style="font-size:90%">${esc(meeting.location)}</span>` : "";
   const time = formatTimeRange(meeting.startTime, meeting.endTime, input.lang);
   const attendeesHtml = buildAttendeesHtml(meeting.attendees);
-  const bgStyle = meeting.rowColor && ROW_COLOR_FILL[meeting.rowColor]
-    ? `background-color:${ROW_COLOR_FILL[meeting.rowColor]};`
+  const hasFill = !!(meeting.rowColor && ROW_COLOR_FILL[meeting.rowColor]);
+  const bgStyle = hasFill ? `background-color:${ROW_COLOR_FILL[meeting.rowColor!]};` : "";
+  const borderStyle = hasFill && ROW_COLOR_BORDER[meeting.rowColor!]
+    ? `border-color:${ROW_COLOR_BORDER[meeting.rowColor!]};`
     : "";
+  const coloredStyle = bgStyle + borderStyle;
 
   const MERGE_COL_INDEX: Record<string, number> = {
     number: 0, meeting: 1, attendees: 2, time: 3,
   };
 
   const cellsLtr: TableCell[] = [
-    { html: esc(String(meeting.dailyNumber)), cls: "num-cell", style: bgStyle },
-    { html: esc(title) + location, cls: "meeting-cell", style: bgStyle },
-    { html: attendeesHtml, cls: "attendees-cell", style: "" },
-    { html: `<span dir="ltr">${esc(time)}</span>`, cls: "time-cell", style: "" },
+    { html: esc(String(meeting.dailyNumber)), cls: "num-cell", style: coloredStyle },
+    { html: esc(title) + location, cls: "meeting-cell", style: coloredStyle },
+    { html: attendeesHtml, cls: "attendees-cell", style: borderStyle },
+    { html: `<span dir="ltr">${esc(time)}</span>`, cls: "time-cell", style: borderStyle },
   ];
 
   const renderCells = (cells: TableCell[], allColored: boolean): string =>
     cells
       .map((c) => {
         const cs = c.colspan ? ` colspan="${c.colspan}"` : "";
-        const bg = allColored ? bgStyle : c.style;
-        return `<td class="${c.cls}" style="${bg}"${cs}>${c.html}</td>`;
+        const st = allColored ? coloredStyle : c.style;
+        return `<td class="${c.cls}" style="${st}"${cs}>${c.html}</td>`;
       })
       .join("");