0.2.24: household-aware GP asset balances + show on Overview

Fixes a linked GP entity showing an empty Assets tab when its capital is
held under the linked account's other legal names (the eNAV often splits
one LLC across names).

- New GET /api/entities/{id}/asset-balances: household-aware, returns the
  linked account's (and its linked names') capital balances per fund, plus
  the linked account name for a clear empty state.
- Assets tab uses it; shows "linked to X but no balances on file" instead
  of a blank table when the wrong account is linked.
- GP/mgmt Overview now surfaces the total linked balance across funds with
  a "View by fund" link, so assets are visible without opening the tab.

Verified: 15/15 backend tests (incl. household case); frontend tsc + vite
build clean.

frontend/src/api.ts

@@ -225,6 +225,12 @@ export interface InvestorView {
   documents: PortalDocument[];
 }
 
+export interface AssetBalances {
+  linked_user_id: number | null;
+  linked_name: string | null;
+  balances: CapitalAccount[];
+}
+
 // --- API helpers ---
 
 export class ApiError extends Error {
@@ -299,6 +305,10 @@ export const api = {
   deleteStake: (entityId: number, stakeId: number) =>
     request<{ status: string }>(`/api/entities/${entityId}/stakes/${stakeId}`, { method: "DELETE" }),
 
+  // A GP/mgmt entity's assets: its linked account's capital balances across the funds.
+  entityAssetBalances: (entityId: number) =>
+    request<AssetBalances>(`/api/entities/${entityId}/asset-balances`),
+
   // Investor View (admin read-only reconstruction of an investor's portal)
   investorView: (userId: number) => request<InvestorView>(`/api/users/${userId}/investor-view`),