feat(dashboard): show the user's work plan for today

Adds a "Můj plán na dnešek" card near the clock-in: for the logged-in
user it shows today's work-plan entry — category (coloured dot + label),
the project/site (the "where"), the note, and a "součást rozsahu …" badge
only for genuinely multi-day ranges. A muted "Pro dnešek nemáte
naplánováno." empty state when nothing is scheduled.

Server: GET /api/admin/dashboard now returns today_plan, reusing
plan.service resolveCell (override-beats-range precedence) for the current
user + today's local (Prague) date, enriched with the category label +
colour so the widget needs no extra query. Gated by attendance.record /
attendance.manage (the plan permission); omitted otherwise. No migration.

Verified in Chrome: renders today's entry (Práce · OBJ-2026-006 — koko)
with the category colour. tsc -b --noEmit, npm run build, vitest 152/152.

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

src/admin/components/dashboard/DashTodayPlan.tsx

@@ -0,0 +1,110 @@
+import Box from "@mui/material/Box";
+import Typography from "@mui/material/Typography";
+import { Card } from "../../ui";
+import { formatDate } from "../../utils/formatters";
+
+/** The logged-in user's resolved work plan for today (see GET /api/admin/dashboard). */
+export interface TodayPlan {
+  shift_date: string;
+  category: string;
+  category_label: string;
+  category_color: string | null;
+  project_id: number | null;
+  project_number: string | null;
+  project_name: string | null;
+  note: string;
+  source: "entry" | "override";
+  rangeFrom: string | null;
+  rangeTo: string | null;
+}
+
+function projectLabel(p: TodayPlan): string {
+  const parts = [p.project_number, p.project_name].filter(Boolean);
+  return parts.length > 0 ? parts.join(" — ") : "Bez projektu";
+}
+
+/**
+ * "Můj plán na dnešek" — shows the logged-in user's work-plan entry for today
+ * (category + project/site + note, with a range badge when the day is part of a
+ * multi-day range). `plan === null` = the user has plan access but nothing is
+ * scheduled today (muted empty state). Rendered near the clock-in on the
+ * dashboard; the caller gates it on the plan permission.
+ */
+export default function DashTodayPlan({ plan }: { plan: TodayPlan | null }) {
+  const color = plan?.category_color || "var(--mui-palette-primary-main)";
+  return (
+    <Card sx={{ mb: 3 }}>
+      <Typography
+        variant="subtitle2"
+        sx={{ mb: 1.5, fontWeight: 600, color: "text.secondary" }}
+      >
+        Můj plán na dnešek
+      </Typography>
+
+      {plan ? (
+        <Box sx={{ display: "flex", flexDirection: "column", gap: 1 }}>
+          <Box
+            sx={{
+              display: "flex",
+              alignItems: "center",
+              gap: 1,
+              flexWrap: "wrap",
+            }}
+          >
+            <Box
+              sx={{
+                display: "inline-flex",
+                alignItems: "center",
+                gap: 0.75,
+                px: 1.25,
+                py: 0.5,
+                borderRadius: 999,
+                border: 1,
+                borderColor: "divider",
+                bgcolor: `color-mix(in srgb, ${color} 12%, transparent)`,
+              }}
+            >
+              <Box
+                sx={{
+                  width: 10,
+                  height: 10,
+                  borderRadius: "50%",
+                  bgcolor: color,
+                  flexShrink: 0,
+                }}
+              />
+              <Typography
+                component="span"
+                sx={{ fontWeight: 700, fontSize: "0.8rem" }}
+              >
+                {plan.category_label}
+              </Typography>
+            </Box>
+            {plan.rangeFrom &&
+              plan.rangeTo &&
+              plan.rangeFrom !== plan.rangeTo && (
+                <Typography variant="caption" color="text.secondary">
+                  součást rozsahu {formatDate(plan.rangeFrom)} –{" "}
+                  {formatDate(plan.rangeTo)}
+                </Typography>
+              )}
+          </Box>
+
+          <Typography variant="h6" sx={{ lineHeight: 1.25 }}>
+            {projectLabel(plan)}
+          </Typography>
+
+          {plan.note && (
+            <Typography variant="body2" color="text.secondary">
+              {plan.note}
+            </Typography>
+          )}
+        </Box>
+      ) : (
+        <Typography variant="body2" color="text.secondary">
+          Pro dnešek nemáte naplánováno.
+        </Typography>
+      )}
+    </Card>
+  );
+}