feat(settings): selectable primary display currency (#63)

components/status/CashBalancePane.tsx

@@ -2,7 +2,8 @@ import { useMemo, useState } from 'react';
 import { Panel } from '../shared';
 import { useBalancesStore } from '../../stores/entities/balances';
 import { useCompanyStore } from '../../stores/company';
-import { primaryCurrencyFor, sortBalances } from '../../lib/currency';
+import { useSettingsStore } from '../../stores/settings';
+import { resolvePrimaryCurrency, sortBalances } from '../../lib/currency';
 
 function formatAmount(amount: number): string {
   return Math.round(amount).toLocaleString('en-US');
@@ -51,15 +52,16 @@ export function CashBalancePane() {
   const fetched = useBalancesStore((s) => s.fetched);
   const entities = useBalancesStore((s) => s.entities);
   const company = useCompanyStore((s) => s.company);
+  const preferredCurrency = useSettingsStore((s) => s.preferredCurrency);
   const [expanded, setExpanded] = useState(false);
 
   const balances = useMemo(
     () =>
       sortBalances(
         Array.from(entities.values()),
-        company ? primaryCurrencyFor(company.countryId) : null
+        resolvePrimaryCurrency(company?.countryId ?? null, preferredCurrency)
       ),
-    [entities, company]
+    [entities, company, preferredCurrency]
   );
 
   const title = company

components/views/SettingsView.tsx

@@ -29,6 +29,16 @@ const refreshModeOptions: { id: RefreshMode; label: string }[] = [
   { id: 'auto', label: 'Auto' },
 ];
 
+// PrUn's currency set is fixed (ECD excluded — legacy, not spendable).
+// null = derive from the company's faction (the unchanged default).
+const primaryCurrencyOptions: { id: string | null; label: string }[] = [
+  { id: null, label: 'Auto' },
+  { id: 'AIC', label: 'AIC' },
+  { id: 'CIS', label: 'CIS' },
+  { id: 'ICA', label: 'ICA' },
+  { id: 'NCC', label: 'NCC' },
+];
+
 /** 24-bit hex number → CSS hex string, for inline preset-preview swatches. */
 function toCssHex(value: number): string {
   return `#${value.toString(16).padStart(6, '0')}`;
@@ -150,7 +160,7 @@ export function validateRepairThresholds(
 }
 
 export function SettingsView() {
-  const { fio, setFioConfig, setFioLastFetch, materialTheme, setMaterialTheme, uiTheme, setUiTheme, burnThresholds, setBurnThresholds } = useSettingsStore();
+  const { fio, setFioConfig, setFioLastFetch, materialTheme, setMaterialTheme, uiTheme, setUiTheme, burnThresholds, setBurnThresholds, preferredCurrency, setPreferredCurrency } = useSettingsStore();
 
   // Burn threshold local state — strings for free-form editing, persist on valid input
   const [critical, setCritical] = useState(String(burnThresholds.critical));
@@ -532,6 +542,31 @@ export function SettingsView() {
         </div>
       </Panel>
 
+      {/* Primary Currency Section */}
+      <Panel title="Primary Currency">
+        <div className="space-y-3">
+          <div className="flex gap-2">
+            {primaryCurrencyOptions.map((option) => (
+              <button
+                key={option.label}
+                onClick={() => setPreferredCurrency(option.id)}
+                className={`flex-1 min-h-touch px-2 py-2 font-mono text-[11px] font-semibold uppercase tracking-wider ${
+                  preferredCurrency === option.id
+                    ? 'bg-prun-yellow text-apxm-bg'
+                    : 'border border-apxm-accent text-apxm-muted'
+                }`}
+              >
+                {option.label}
+              </button>
+            ))}
+          </div>
+          <p className="text-xs text-apxm-muted">
+            The headline balance on the Status tab. Auto uses your company&apos;s
+            faction currency.
+          </p>
+        </div>
+      </Panel>
+
       {/* UI Theme Section */}
       <Panel title="Theme">
 

components/views/__tests__/SettingsView.test.ts

@@ -47,6 +47,23 @@ describe('SettingsView repair threshold validation', () => {
   });
 });
 
+describe('preferred currency setting (#63)', () => {
+  beforeEach(() => {
+    useSettingsStore.getState().reset();
+  });
+
+  it('defaults to null (faction-derived headline currency)', () => {
+    expect(useSettingsStore.getState().preferredCurrency).toBeNull();
+  });
+
+  it('setPreferredCurrency round-trips a code and back to Auto', () => {
+    useSettingsStore.getState().setPreferredCurrency('NCC');
+    expect(useSettingsStore.getState().preferredCurrency).toBe('NCC');
+    useSettingsStore.getState().setPreferredCurrency(null);
+    expect(useSettingsStore.getState().preferredCurrency).toBeNull();
+  });
+});
+
 describe('SettingsView burn threshold validation', () => {
   describe('validateThresholds', () => {
     it('returns null for valid thresholds', () => {

lib/__tests__/currency.test.ts

@@ -1,5 +1,5 @@
 import { describe, it, expect } from 'vitest';
-import { primaryCurrencyFor, sortBalances } from '../currency';
+import { primaryCurrencyFor, resolvePrimaryCurrency, sortBalances } from '../currency';
 import type { PrunApi } from '../../types/prun-api';
 
 function balance(currency: string, amount = 1000): PrunApi.CurrencyAmount {
@@ -24,6 +24,27 @@ describe('primaryCurrencyFor', () => {
   });
 });
 
+describe('resolvePrimaryCurrency', () => {
+  const AI_GUID = '18419e6fd11b5af8bf0d0a996ad1a622';
+
+  it('override wins over the faction-derived currency (#63)', () => {
+    expect(resolvePrimaryCurrency(AI_GUID, 'NCC')).toBe('NCC');
+  });
+
+  it('falls back to the faction currency when no override is set', () => {
+    expect(resolvePrimaryCurrency(AI_GUID, null)).toBe('AIC');
+  });
+
+  it('override works even without company data', () => {
+    expect(resolvePrimaryCurrency(null, 'CIS')).toBe('CIS');
+  });
+
+  it('returns null with no override and no/unknown countryId', () => {
+    expect(resolvePrimaryCurrency(null, null)).toBeNull();
+    expect(resolvePrimaryCurrency('unknown-guid', null)).toBeNull();
+  });
+});
+
 describe('sortBalances', () => {
   it('filters out ECD', () => {
     const result = sortBalances([balance('ECD'), balance('AIC')], null);

lib/currency.ts

@@ -25,6 +25,19 @@ export function primaryCurrencyFor(countryId: string): string | null {
   return COUNTRY_CURRENCY[countryId] ?? null;
 }
 
+/**
+ * The currency to headline in the liquidity pane. A user override wins —
+ * players often trade in a non-faction currency based on where they operate
+ * (issue #63) — otherwise fall back to the faction-derived primary.
+ */
+export function resolvePrimaryCurrency(
+  countryId: string | null,
+  override: string | null
+): string | null {
+  if (override) return override;
+  return countryId ? primaryCurrencyFor(countryId) : null;
+}
+
 /**
  * Display order for the liquidity list: ECD filtered out (legacy currency,
  * not spendable), the company's primary currency first, remaining

stores/settings.ts

@@ -55,6 +55,10 @@ interface SettingsState {
    *  Opt-in per the action-authorisation rule. No UI yet — the Settings
    *  toggle lands with the ACT views (#25 Phase D). */
   autoConfirm: boolean;
+  /** Headline currency for the liquidity pane. null (default) derives it from
+   *  the company's faction; a currency code overrides — players often trade
+   *  in a non-faction currency based on location (#63). */
+  preferredCurrency: string | null;
 }
 
 interface SettingsActions {
@@ -69,6 +73,7 @@ interface SettingsActions {
   setNoBuy: (tickers: string[]) => void;
   setRefreshMode: (mode: RefreshMode) => void;
   setAutoConfirm: (enabled: boolean) => void;
+  setPreferredCurrency: (currency: string | null) => void;
   reset: () => void;
 }
 
@@ -96,6 +101,7 @@ const initialState: SettingsState = {
   noBuy: [],
   refreshMode: 'manual',
   autoConfirm: false,
+  preferredCurrency: null,
 };
 
 // Check if browser storage API is available
@@ -195,6 +201,7 @@ export const useSettingsStore = create<SettingsStore>()(
       setNoBuy: (tickers) => set({ noBuy: tickers }),
       setRefreshMode: (mode) => set({ refreshMode: mode }),
       setAutoConfirm: (enabled) => set({ autoConfirm: enabled }),
+      setPreferredCurrency: (currency) => set({ preferredCurrency: currency }),
 
       reset: () => set(initialState),
     }),