fix(attendance): stop the page + leave modal overflowing (grid minmax + minWidth:0)

Two overflow fixes on Attendance.tsx: (1) the leave-request modal's Od/Do date row used a bare gridTemplateColumns '1fr 1fr', whose minmax(auto,1fr) tracks couldn't shrink below the two DatePickers' min-content, overflowing the narrow modal (horizontal scroll, 'Do' clipped) — now minmax(0,1fr). (2) On phones the whole page overflowed: the main two-column grid used { xs: '1fr' }, and the left column's 5-col 'Dnešní dokončené směny' table forced a 477px min-content (the TableContainer's overflow-x:auto never engaged because the grid item had min-width:auto). Now the grid uses minmax(0,1fr) and both columns get minWidth:0, so the table scrolls inside its container and the page fits the viewport. Verified at 390px width via DOM measurement.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/admin/pages/Attendance.tsx

@@ -630,13 +630,16 @@ export default function Attendance() {
       <Box
         sx={{
           display: "grid",
-          gridTemplateColumns: { xs: "1fr", lg: "1fr 340px" },
+          gridTemplateColumns: {
+            xs: "minmax(0, 1fr)",
+            lg: "minmax(0, 1fr) 340px",
+          },
           gap: 3,
           alignItems: "start",
         }}
       >
         {/* Left Column - Clock In/Out */}
-        <Box>
+        <Box sx={{ minWidth: 0 }}>
           <Card>
             <Box
               sx={{
@@ -979,7 +982,9 @@ export default function Attendance() {
         </Box>
 
         {/* Right Column - Stats & Quick Links */}
-        <Box sx={{ display: "flex", flexDirection: "column", gap: 3 }}>
+        <Box
+          sx={{ display: "flex", flexDirection: "column", gap: 3, minWidth: 0 }}
+        >
           {/* Leave Balance Card */}
           <StatCard
             icon={VacationIcon}
@@ -1169,7 +1174,7 @@ export default function Attendance() {
         <Box
           sx={{
             display: "grid",
-            gridTemplateColumns: "1fr 1fr",
+            gridTemplateColumns: "minmax(0, 1fr) minmax(0, 1fr)",
             gap: 2,
           }}
         >