style(quotes): stack company under customer in the same column

Customer and Company used to be two side-by-side DataTable columns,
which cost ~120 px of horizontal width and made rows feel sparse when
the operator is just eyeballing who's-who across many quotes.

Now the Customer column carries both names in one cell: customer in
the default font-medium row, company underneath in text-xs
text-muted-foreground so the visual hierarchy reads as
"Primary person  >  Their organisation".

Effect on row layout:
- Total table column count drops from 7 to 6.
- Row width shrinks on desktop, freeing space for the larger
  Quote # column (which carries the follow-up / replied / aged
  chips and was getting crowded).
- The mobile card render (used below the sm breakpoint) gets the
  same stacking so the company line shows on every viewport.

Edge cases handled:
- Both names empty             → '—' muted placeholder
- Customer present, no company → just the customer name
- Company present, no customer → '—' for the customer, company below
- Very long names              → truncate via className='truncate'

The existing standalone Company column is removed; downstream
code (DataTable, mobileCardRender) reads from the same expanded
fields so no extra fetches.

src/app/(app)/quotes/page.tsx

@@ -410,14 +410,31 @@ export default function QuotesPage() {
             ),
           },
           {
+            // Customer column also carries the Company underneath as a
+            // small muted sub-line — collapses the row width by ~120 px
+            // and makes the list easier to scan when the operator is
+            // visual-eyeballing who's-who across many rows.
             key: "customer",
             label: "Customer",
-            render: (item: Quote) => <span>{item.expand?.customer?.customer || "—"}</span>,
-          },
-          {
-            key: "company",
-            label: "Company",
-            render: (item: Quote) => <span>{item.expand?.company?.company || "—"}</span>,
+            render: (item: Quote) => {
+              const customerName = item.expand?.customer?.customer;
+              const companyName = item.expand?.company?.company;
+              if (!customerName && !companyName) {
+                return <span className="text-muted-foreground">—</span>;
+              }
+              return (
+                <div className="flex flex-col gap-0.5 leading-tight">
+                  {customerName ? (
+                    <span className="font-medium">{customerName}</span>
+                  ) : (
+                    <span className="text-muted-foreground">—</span>
+                  )}
+                  {companyName ? (
+                    <span className="text-xs text-muted-foreground">{companyName}</span>
+                  ) : null}
+                </div>
+              );
+            },
           },
           {
             key: "rep",
@@ -606,9 +623,16 @@ export default function QuotesPage() {
                       {hasCustomerReply(item) && <RepliedChip repliedAt={item.last_reply_at} />}
                       {isAged(item) && <AgedBadge created={item.created} />}
                     </div>
-                    <p className="text-sm text-muted-foreground truncate">
-                      {item.expand?.customer?.customer || "—"}
-                    </p>
+                    <div className="leading-tight">
+                      <p className="text-sm font-medium truncate">
+                        {item.expand?.customer?.customer || "—"}
+                      </p>
+                      {item.expand?.company?.company ? (
+                        <p className="text-xs text-muted-foreground truncate">
+                          {item.expand.company.company}
+                        </p>
+                      ) : null}
+                    </div>
                   </div>
                 </div>
                 <Badge variant="outline" className={quoteStatusClassName(item.status)}>