fix(ui): humanize enum labels, format dates, resolve actor names, loading skeleton

- Documents hub signer status now renders via a label map (`Pending`,
  `Signed`, `Declined`, …) instead of the raw lowercase enum value.
- Invoice detail formats `dueDate` and `paymentDate` as `MMM d, yyyy`
  via `date-fns` instead of leaking raw `2025-03-14` ISO strings, and
  swaps the "Payment Method" free-text input for a `Select` of labelled
  options (`Bank transfer`, `Credit card`, …) so we never store
  `bank_transfer` from a hand-typed field again.
- Interest tabs `MilestoneSection` status badge uses a `humanizeStatus`
  helper so values like `waiting_for_signatures` show as
  `Waiting For Signatures` (correctly title-cased) instead of being a
  lower-snake-case fragment inside an ALL-CAPS pill.
- `OUTCOME_BADGE` in the interest header now has a fall-through that
  renders any unknown outcome as a closed-state badge, preventing a
  closed interest from looking open just because its enum was added
  upstream without a matching label entry.
- Interest timeline route joins the `user` table and returns
  `userName` alongside `userId`; the client renders the resolved name
  instead of a 36-char UUID. Falls back to `'a teammate'` if the user
  row was deleted.
- Invoice "New / Step 3 — Review" replaces the truncated UUID display
  with a server-resolved client/company name via a small `useQuery`,
  so users can confirm they picked the right billing entity before
  submitting.
- New `loading.tsx` for client detail renders a header / tab strip /
  card skeleton during the server-component / initial-query window
  that previously flashed empty.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/app/(dashboard)/[portSlug]/clients/[clientId]/loading.tsx

@@ -0,0 +1,41 @@
+import { Skeleton } from '@/components/ui/skeleton';
+import { CardSkeleton } from '@/components/shared/loading-skeleton';
+
+/**
+ * Route-level loading UI for the client detail page. Renders while the
+ * server component resolves the session and the client component bootstraps
+ * its initial query — replaces the previous empty-header flash on direct
+ * URL visits.
+ */
+export default function Loading() {
+  return (
+    <div className="space-y-6">
+      {/* Header strip — title, badges, action buttons */}
+      <div className="rounded-xl border border-border bg-card px-5 py-4 shadow-sm space-y-3">
+        <div className="flex items-center gap-3">
+          <Skeleton className="h-7 w-56" />
+          <Skeleton className="h-5 w-16 rounded-full" />
+        </div>
+        <div className="flex flex-wrap gap-2">
+          <Skeleton className="h-9 w-20 rounded-md" />
+          <Skeleton className="h-9 w-20 rounded-md" />
+          <Skeleton className="h-9 w-24 rounded-md" />
+          <Skeleton className="h-9 w-32 rounded-md" />
+        </div>
+      </div>
+
+      {/* Tab strip */}
+      <div className="flex gap-2 border-b border-border pb-1">
+        {Array.from({ length: 8 }).map((_, i) => (
+          <Skeleton key={i} className="h-8 w-20 rounded-md" />
+        ))}
+      </div>
+
+      {/* Two-column overview */}
+      <div className="grid grid-cols-1 gap-6 md:grid-cols-2">
+        <CardSkeleton />
+        <CardSkeleton />
+      </div>
+    </div>
+  );
+}