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-api/src/scripts/seed-occ-july-2026.ts

@@ -487,6 +487,12 @@ async function upsertTrain(ds: DataSource, code: string): Promise<string> {
   return row.id;
 }
 
+/** The handling window a stop records — the loading/unloading report's input. */
+interface Handling {
+  unloadingStartedAt: Date;
+  loadingCompletedAt: Date;
+}
+
 async function upsertCheckpoint(
   ds: DataSource,
   scheduleId: string,
@@ -495,7 +501,18 @@ async function upsertCheckpoint(
   kind: 'ARRIVED' | 'DEPARTED',
   occurredAt: Date,
   note: string,
+  handling?: Handling,
 ): Promise<void> {
+  const params = [
+    scheduleId,
+    yardId,
+    sequenceNo,
+    kind,
+    occurredAt,
+    note,
+    handling?.unloadingStartedAt ?? null,
+    handling?.loadingCompletedAt ?? null,
+  ];
   const existing = await ds.query<Array<{ id: string }>>(
     `SELECT id FROM freight.train_checkpoint_events
       WHERE train_schedule_id = $1 AND yard_id = $2 AND kind = $3 AND deleted_at IS NULL`,
@@ -503,17 +520,20 @@ async function upsertCheckpoint(
   );
   if (existing.length) {
     await ds.query(
-      `UPDATE freight.train_checkpoint_events SET occurred_at = $2, note = $3, updated_at = now()
+      `UPDATE freight.train_checkpoint_events
+          SET occurred_at = $2, note = $3,
+              unloading_started_at = $4, loading_completed_at = $5, updated_at = now()
         WHERE id = $1`,
-      [existing[0].id, occurredAt, note],
+      [existing[0].id, occurredAt, note, params[6], params[7]],
     );
     return;
   }
   await ds.query(
     `INSERT INTO freight.train_checkpoint_events
-       (train_schedule_id, yard_id, sequence_no, kind, occurred_at, note)
-     VALUES ($1, $2, $3, $4, $5, $6)`,
-    [scheduleId, yardId, sequenceNo, kind, occurredAt, note],
+       (train_schedule_id, yard_id, sequence_no, kind, occurred_at, note,
+        unloading_started_at, loading_completed_at)
+     VALUES ($1, $2, $3, $4, $5, $6, $7, $8)`,
+    params,
   );
 }
 
@@ -605,13 +625,17 @@ async function seedDmpTrains(ds: DataSource, ids: Ids): Promise<void> {
       arrivedAt: arrivedGelan,
     });
 
-    // The loading/unloading figure has nowhere of its own to live yet — no
-    // table records when handling starts and ends — so it rides on the stop's
-    // note, where the staying-time report surfaces it as the stop's reason.
+    // The measured handling window, on the arrival row the staying-time report
+    // builds the stop from: work starts when the train lands and ends when
+    // loading finishes, which is what the OCC figure measures. The rest of the
+    // stay reports as other activity.
     const note =
       `OCC July 2026 — loading/unloading ${handlingHours.toFixed(2)}h of ` +
       `${stayingHours.toFixed(2)}h total staying`;
-    await upsertCheckpoint(ds, schedule, dmp, 0, 'ARRIVED', arrivedAtDmp, note);
+    await upsertCheckpoint(ds, schedule, dmp, 0, 'ARRIVED', arrivedAtDmp, note, {
+      unloadingStartedAt: arrivedAtDmp,
+      loadingCompletedAt: addHours(arrivedAtDmp, handlingHours),
+    });
     await upsertCheckpoint(ds, schedule, dmp, 0, 'DEPARTED', departedDmp, note);
   }
   console.log(`DMP trains      : ${DMP_TRAINS.length} trains with measured staying times`);