Task #747: executive meetings table — square corners + tighter rows

- executive-meetings.tsx: removed rounded-md from the schedule table
  wrapper and rounded-t-md from the sticky floating thead; navy 2px
  border unchanged, corners now fully square.
- Reduced vertical padding in tbody cells: meeting/attendees/time/merged
  cells py-3→py-1.5, number cell py-2→py-1.5.
- AttendeesCell split-mode group wrapper space-y-2→space-y-1 to shrink
  the empty gaps in multi-group attendee rows (screenshot complaint).
- Print thead and screen thead paddings untouched; no behavior changes.
- tx-os tsc clean; architect review passed.

artifacts/tx-os/src/pages/executive-meetings.tsx

@@ -3169,7 +3169,7 @@ function ScheduleSection({
           paginated output. */}
       <div
         data-testid="em-sticky-thead"
-        className="sticky z-[6] overflow-hidden bg-white border-x-2 border-t-2 border-[#0B1E3F] rounded-t-md shadow-[0_4px_6px_-4px_rgba(11,30,63,0.15)] print:hidden"
+        className="sticky z-[6] overflow-hidden bg-white border-x-2 border-t-2 border-[#0B1E3F] shadow-[0_4px_6px_-4px_rgba(11,30,63,0.15)] print:hidden"
         style={{
           top: "calc(var(--em-header-h, 0px) + var(--em-heading-h, 0px))",
         }}
@@ -3265,7 +3265,7 @@ function ScheduleSection({
 
       <div
         ref={tableWrapperRef}
-        className="bg-white border-2 border-[#0B1E3F] rounded-md overflow-x-auto shadow-sm print:shadow-none print:border-black print:overflow-hidden"
+        className="bg-white border-2 border-[#0B1E3F] overflow-x-auto shadow-sm print:shadow-none print:border-black print:overflow-hidden"
         id="executive-schedule-printable"
       >
         <table
@@ -4434,7 +4434,7 @@ function MeetingRow({
   }, [listeners, effectiveDragEnabled, isSkipDragTarget]);
 
   const numberCellCls =
-    "border border-gray-300 px-2 py-2 text-center align-middle font-semibold " +
+    "border border-gray-300 px-2 py-1.5 text-center align-middle font-semibold " +
     (highlight || isCancelled
       ? "bg-red-600 text-white"
       : "bg-white text-[#0B1E3F]");
@@ -4637,7 +4637,7 @@ function MeetingRow({
         return (
           <td
             key="meeting"
-            className={`border border-gray-300 px-3 py-3 align-middle text-center ${meeting.isExternal ? "text-[#dc2626]" : "text-[#0B1E3F]"} relative group`}
+            className={`border border-gray-300 px-3 py-1.5 align-middle text-center ${meeting.isExternal ? "text-[#dc2626]" : "text-[#0B1E3F]"} relative group`}
             style={tintedCellStyle(col, true)}
           >
             <EditableCell
@@ -4670,7 +4670,7 @@ function MeetingRow({
         return (
           <td
             key="attendees"
-            className="border border-gray-300 px-3 py-3 align-middle text-center relative group"
+            className="border border-gray-300 px-3 py-1.5 align-middle text-center relative group"
             style={tintedCellStyle(col, false)}
           >
             <AttendeesCell
@@ -4691,7 +4691,7 @@ function MeetingRow({
         return (
           <td
             key="time"
-            className="border border-gray-300 px-3 py-3 align-middle text-center relative group"
+            className="border border-gray-300 px-3 py-1.5 align-middle text-center relative group"
             style={tintedCellStyle(col, false)}
           >
             <TimeRangeCell
@@ -4732,7 +4732,7 @@ function MeetingRow({
           <td
             key="merge"
             colSpan={span}
-            className="border border-gray-300 px-3 py-3 align-middle text-[#0B1E3F] relative group"
+            className="border border-gray-300 px-3 py-1.5 align-middle text-[#0B1E3F] relative group"
             style={{
               width: totalWidth,
               overflow: "hidden",
@@ -5650,7 +5650,7 @@ function AttendeesCell({
     // suppress its own trailing subheading chip. Per-group "+" person
     // chips and the after-section chips are unaffected.
     return (
-      <div className="space-y-2">
+      <div className="space-y-1">
         {(virtual.length > 0 || isPendingForType("virtual")) && (
           <AttendeeGroup
             label={