feat(rates): last-mile rate rules with bulk per-ton-km and container distance bands

- rates: min_km/max_km columns, PER_TON_KM unit, ETB|USD currency for last mile
- extend UQ_rates_pattern with band start; overlap + shape validation
- shared last-mile charge resolver; approve-dialog price estimate endpoint
- delivery-fee invoice prices via rules, falls back to vehicle price/km
- backoffice: last-mile rate form (mode, container type, band, currency)

apps/edr-freight-web/backoffice/src/components/operations/LastMileRequestsPanel.tsx

@@ -1,4 +1,4 @@
-import { useState } from "react";
+import { useEffect, useState } from "react";
 import {
   Badge,
   Box,
@@ -76,6 +76,21 @@ export function LastMileRequestsPanel() {
     queryFn: async () => (await lastMileRequestsService.freeTruckCount()).data,
   });
 
+  // Rule-based estimate for the approve dialog (estimated km × live last-mile
+  // rates). Prefills the advance once, without clobbering a typed value.
+  const { data: estimate } = useQuery({
+    queryKey: QUERY_KEYS.LAST_MILE_REQUESTS.priceEstimate(approveTarget?.id ?? ""),
+    queryFn: async () =>
+      (await lastMileRequestsService.priceEstimate(approveTarget!.id)).data,
+    enabled: Boolean(approveTarget),
+  });
+  useEffect(() => {
+    if (approveTarget && estimate?.total != null && advanceAmount === "") {
+      setAdvanceAmount(estimate.total);
+    }
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [estimate, approveTarget]);
+
   const invalidate = () =>
     qc.invalidateQueries({ queryKey: QUERY_KEYS.LAST_MILE_REQUESTS.ROOT });
 
@@ -227,11 +242,29 @@ export function LastMileRequestsPanel() {
 
       <Modal
         opened={Boolean(approveTarget)}
-        onClose={() => setApproveTarget(null)}
+        onClose={() => {
+          setApproveTarget(null);
+          setAdvanceAmount("");
+        }}
         title={<Text fw={700}>Approve request{approveTarget?.booking?.reference ? ` · ${approveTarget.booking.reference}` : ""}</Text>}
         centered
       >
         <Stack gap="md">
+          {estimate?.total != null && (
+            <Stack gap={4}>
+              {estimate.lines.map((line) => (
+                <Text key={line.description} size="xs" c="dimmed">
+                  {line.description} — {line.amount.toLocaleString()}
+                </Text>
+              ))}
+              <Text size="sm" fw={600}>
+                Estimated total: {estimate.total.toLocaleString()} {estimate.currency}
+                {estimate.estimatedKm != null
+                  ? ` · ${estimate.estimatedKm} km (straight-line estimate)`
+                  : ""}
+              </Text>
+            </Stack>
+          )}
           <NumberInput
             label="Advance amount"
             placeholder="0.00"
@@ -241,7 +274,13 @@ export function LastMileRequestsPanel() {
             onChange={setAdvanceAmount}
           />
           <Group justify="flex-end">
-            <Button variant="default" onClick={() => setApproveTarget(null)}>
+            <Button
+              variant="default"
+              onClick={() => {
+                setApproveTarget(null);
+                setAdvanceAmount("");
+              }}
+            >
               Cancel
             </Button>
             <Button