feat(reports): record loading and unloading time per stop

The OCC report publishes total loading and unloading time and the other
activity left over from a station stay, but nothing recorded when handling
started or ended — the July 2026 seed had to write the figure into a
checkpoint note. Four nullable stamps now ride the stop's arrival row, which
is the row the staying-time report builds a stay from (a turnaround's
departure belongs to a different schedule).

Handling is unloading start to loading end, so a container stop reads as one
window and a bulk station that only loads or only unloads still reports its
half; other activity is the rest of the stay. Both stay NULL where nothing
was logged rather than collapsing to zero.

- station-staying-time: + loading/unloading and other activity per stop
- turnaround-cycle: + the same, summed over the cycle's stops
- loading-unloading (new): per train per station per period, so a week or
  month view is that train's average over its stops
- the stop/stay query moves to operations-classification, shared by both

apps/edr-freight-web/backoffice/src/components/trainScheduling/CheckpointTimeModal.tsx

@@ -1,13 +1,38 @@
-import { Button, Group, Modal, Stack, Text, Textarea } from "@mantine/core";
+import { Button, Divider, Group, Modal, SimpleGrid, Stack, Text, Textarea } from "@mantine/core";
 import { DateTimePicker } from "@mantine/dates";
 import { useMediaQuery } from "@mantine/hooks";
 import { useEffect, useState } from "react";
 
+import type { CheckpointHandlingTimes } from "@/types/trainScheduling";
+
+/** The four station-work stamps, in the order they happen. */
+const HANDLING_FIELDS = [
+  ["unloadingStartedAt", "Unloading started"],
+  ["unloadingCompletedAt", "Unloading finished"],
+  ["loadingStartedAt", "Loading started"],
+  ["loadingCompletedAt", "Loading finished"],
+] as const;
+
+type HandlingField = (typeof HANDLING_FIELDS)[number][0];
+type HandlingState = Record<HandlingField, Date | null>;
+
+const EMPTY_HANDLING: HandlingState = {
+  unloadingStartedAt: null,
+  unloadingCompletedAt: null,
+  loadingStartedAt: null,
+  loadingCompletedAt: null,
+};
+
 /**
- * Time + note for one leg of a train's journey — used both to log a pass
- * (defaults to now) and to correct an already-logged leg (prefilled). Past
- * times are allowed (staff record after the fact); the future is not, and the
- * server additionally keeps legs in corridor order.
+ * Time, station work and note for one leg of a train's journey — used both to
+ * log a pass (defaults to now) and to correct an already-logged leg
+ * (prefilled). Past times are allowed (staff record after the fact); the future
+ * is not, and the server additionally keeps legs in corridor order.
+ *
+ * The four handling stamps are what the loading-and-unloading reports measure:
+ * total handling is unloading start to loading end, and whatever is left of the
+ * stay is other activity. All four are optional — a stop logged without them
+ * still reports its staying time.
  */
 export function CheckpointTimeModal({
   opened,
@@ -17,6 +42,7 @@ export function CheckpointTimeModal({
   description,
   initialOccurredAt,
   initialNote,
+  initialHandling,
   submitLabel,
   submitColor = "edr-green",
   loading,
@@ -30,19 +56,37 @@ export function CheckpointTimeModal({
   /** ISO; omit to default to now. */
   initialOccurredAt?: string | null;
   initialNote?: string | null;
+  initialHandling?: CheckpointHandlingTimes | null;
   submitLabel: string;
   submitColor?: string;
   loading: boolean;
-  onSubmit: (values: { occurredAt: string; note: string }) => void;
+  onSubmit: (
+    values: { occurredAt: string; note: string } & Record<HandlingField, string | null>,
+  ) => void;
 }) {
   const isSmallScreen = useMediaQuery("(max-width: 48em)");
   const [at, setAt] = useState<Date | null>(null);
   const [note, setNote] = useState("");
+  const [handling, setHandling] = useState<HandlingState>(EMPTY_HANDLING);
   useEffect(() => {
     if (!opened) return;
     setAt(initialOccurredAt ? new Date(initialOccurredAt) : new Date());
     setNote(initialNote ?? "");
-  }, [opened, initialOccurredAt, initialNote]);
+    setHandling({
+      unloadingStartedAt: initialHandling?.unloadingStartedAt
+        ? new Date(initialHandling.unloadingStartedAt)
+        : null,
+      unloadingCompletedAt: initialHandling?.unloadingCompletedAt
+        ? new Date(initialHandling.unloadingCompletedAt)
+        : null,
+      loadingStartedAt: initialHandling?.loadingStartedAt
+        ? new Date(initialHandling.loadingStartedAt)
+        : null,
+      loadingCompletedAt: initialHandling?.loadingCompletedAt
+        ? new Date(initialHandling.loadingCompletedAt)
+        : null,
+    });
+  }, [opened, initialOccurredAt, initialNote, initialHandling]);
 
   return (
     <Modal
@@ -76,6 +120,35 @@ export function CheckpointTimeModal({
           clearable={false}
           radius="md"
         />
+
+        <Divider
+          label="Station work (optional)"
+          labelPosition="left"
+          styles={{ label: { fontWeight: 600 } }}
+        />
+        <Text size="xs" c="dimmed" mt={-8}>
+          Loading and unloading times for this stop. Total handling is unloading start to
+          loading finish; the rest of the stay reports as other activity.
+        </Text>
+        <SimpleGrid cols={{ base: 1, sm: 2 }} spacing="sm">
+          {HANDLING_FIELDS.map(([field, label]) => (
+            <DateTimePicker
+              key={field}
+              label={label}
+              value={handling[field]}
+              onChange={(v) =>
+                setHandling((prev) => ({ ...prev, [field]: v ? new Date(v) : null }))
+              }
+              maxDate={new Date()}
+              dropdownType={isSmallScreen ? "modal" : "popover"}
+              popoverProps={{ withinPortal: true }}
+              valueFormat="DD MMM YYYY HH:mm"
+              clearable
+              radius="md"
+            />
+          ))}
+        </SimpleGrid>
+
         <Textarea
           label="Note"
           placeholder="Optional"
@@ -96,7 +169,15 @@ export function CheckpointTimeModal({
             loading={loading}
             disabled={!at}
             onClick={() =>
-              at && onSubmit({ occurredAt: at.toISOString(), note: note.trim() })
+              at &&
+              onSubmit({
+                occurredAt: at.toISOString(),
+                note: note.trim(),
+                unloadingStartedAt: handling.unloadingStartedAt?.toISOString() ?? null,
+                unloadingCompletedAt: handling.unloadingCompletedAt?.toISOString() ?? null,
+                loadingStartedAt: handling.loadingStartedAt?.toISOString() ?? null,
+                loadingCompletedAt: handling.loadingCompletedAt?.toISOString() ?? null,
+              })
             }
           >
             {submitLabel}