Add firma flag to availability and show office/home label

Server query gets the last stamp's BU_TERM in the same OUTER APPLY
as LAST_STAMP, exposing FIRMA (1 = Zeiterfassung/Büro). Three OUTER
APPLYs reduced to two by combining MAX(BU_BU) with TOP 1 ORDER BY.

Client model gains a firma boolean and the people-tile indicator
appends "· Büro" or "· Home" next to the timestamp, but only when
the user is logged in.

client/src/availability.ts

@@ -71,7 +71,11 @@ export class Availability {
       var pad = (n: number) => n.toString().padStart(2, '0')
       time = pad(d.getDate()) + '.' + pad(d.getMonth() + 1) + '. ' + pad(d.getHours()) + ':' + pad(d.getMinutes())
     }
-    indicator.innerHTML = '<span class="tapi-dot ' + dotClass + '"></span><small>' + time + '</small>'
+    var location = ''
+    if (entry.loggedIn) {
+      location = entry.firma ? ' · Büro' : ' · Home'
+    }
+    indicator.innerHTML = '<span class="tapi-dot ' + dotClass + '"></span><small>' + time + location + '</small>'
   }
 
   private updateSquare(square: HTMLElement) {