the folder name is served, not derived three times

Mobile asked for `/targets` to carry each person's display name as the folder will
be named, so a picker can honestly say where files will appear. Right request: the
writer already computes that exact string to create a directory, and any client
computing its own would eventually disagree with it — which means telling somebody
the wrong place to look.

So `displayNameFor` is the one definition and the writer calls it too. `/targets`
gains `displayName` per person, and `myFolder` for the whole response: files land
in the RECIPIENT's tree under the SENDER's name, so that is one value rather than
a field on each row. The two are easy to confuse and the distinction matters — a
picker showing `displayName` as the destination folder would name the wrong one.

The web panel now uses both instead of its own copy of the fallback.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/workspaces/officerdev/src/apps/SendOff/SendOffPanel.tsx

@@ -17,7 +17,7 @@ type Target = { kind: 'machine'; name: string } | { kind: 'user'; id: number; na
  * needed keeping in sync.
  */
 export const SendOffPanel = () => {
-  const { devices, people, isLoading } = useSendOffTargets();
+  const { devices, people, myFolder, isLoading } = useSendOffTargets();
   const send = useSendOff();
   const [files, setFiles] = useState<File[]>([]);
   const [target, setTarget] = useState<Target | null>(null);
@@ -107,10 +107,12 @@ export const SendOffPanel = () => {
                 icon={User}
                 heading="People"
                 empty="Nobody has allowed you to send to them yet."
+                // `displayName` from the server, never computed here: it is the folder the writer will
+                // create, and a picker that guessed it would sooner or later name the wrong directory.
                 options={people.map((p) => ({
                   key: `u:${p.id}`,
-                  name: label(p),
-                  target: { kind: 'user' as const, id: p.id, name: label(p) },
+                  name: p.displayName,
+                  target: { kind: 'user' as const, id: p.id, name: p.displayName },
                 }))}
                 selected={target}
                 onSelect={setTarget}
@@ -126,6 +128,11 @@ export const SendOffPanel = () => {
           </Button>
           {/* The server's own message, not a generic one: a file over the limit and a recipient who has
               revoked you are different problems with different answers. */}
+          {target?.kind === 'user' && myFolder && (
+            <p className="text-xs text-muted-foreground">
+              Lands in their <span className="text-foreground">Documents/SendOff/{myFolder}</span>.
+            </p>
+          )}
           {send.error && <p className="text-sm text-destructive">{send.error.message}</p>}
           {send.data && (
             <p className="text-sm text-muted-foreground">

src/workspaces/officerdev/src/apps/SendOff/useSendOff.ts

@@ -3,7 +3,9 @@ import { useClient } from 'hooks/useClient';
 
 export type SendOffDevice = { id: string; name: string; platform: string | null; lastSeenAt: string };
 export type SendOffPerson = { id: number; email: string; name: string | null };
-type Targets = { devices: SendOffDevice[]; people: SendOffPerson[] };
+/** As served by `/targets` — `displayName` is the folder name, computed once on the server. */
+export type SendOffTargetPerson = SendOffPerson & { displayName: string };
+type Targets = { devices: SendOffDevice[]; people: SendOffTargetPerson[]; myFolder: string };
 type Senders = { allowed: SendOffPerson[]; candidates: (SendOffPerson & { allowed: boolean })[] };
 
 const TARGETS = ['sendoff', 'targets'];
@@ -19,7 +21,7 @@ export function useSendOffTargets() {
     // two-row query — the panel is the only reader and it is open for seconds at a time.
     staleTime: 0,
   });
-  return { devices: data?.devices ?? [], people: data?.people ?? [], isLoading, error };
+  return { devices: data?.devices ?? [], people: data?.people ?? [], myFolder: data?.myFolder ?? '', isLoading, error };
 }
 
 /** Who I have allowed to send to me — the consent list, which only I can change. */