fix: 2026-06-09 full-codebase audit hardening

Validation: shared NaN-guarded Zod coercion helpers in schemas/common.ts replace
the raw number|string transform idiom across every schema (the root-cause NaN bug
class); emailOrEmpty + lenient isoDateString/timeString.

Security: roles privilege-escalation closed; refresh-token family revocation on
reuse; TOTP uses config params; read endpoints permission-guarded; received-invoices
gross VAT on all paths; orders-pdf custom-items authz.

Concurrency: $queryRaw SELECT...FOR UPDATE locks in ascending-id order (warehouse
confirm/cancel, attendance lockUserRow); uniqueness checks moved into create
transactions (TOCTOU -> 409); deterministic id tiebreak on second-precision
timestamp ordering (plan resolveCell/resolveGrid, warehouse FIFO).

Frontend: Rules-of-Hooks fixed across ~14 pages + PlanCellModal; UTC-date persisted
fields; dashboard invalidation gaps; stale-closure confirm bugs.

Tooling/tests: ESLint flat config (react-hooks/rules-of-hooks = error) + Prettier;
tsconfig.test.json so tsc -b type-checks the tests; removed 3 dead deps; npm audit
fix (8 -> 3). Suite 195 -> 247 (happy-path auth, FIFO oldest-first, flakiness fixes),
isolated on app_test via .env.test with a hard-throw setup guard.

Gates: tsc 0 | build 0 | vitest 247/247 | eslint 0 errors.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/admin/ui/Tabs.tsx

@@ -8,6 +8,11 @@ export interface TabDef {
   label: string;
 }
 
+// Deterministic ids so the Tab control and its TabPanel can cross-reference for
+// a11y (aria-controls <-> aria-labelledby). Values are app-controlled strings.
+const tabId = (value: string) => `tab-${value}`;
+const panelId = (value: string) => `tabpanel-${value}`;
+
 /** Tab bar over MUI Tabs. Pair with <TabPanel> for the content. */
 export function Tabs({
   value,
@@ -30,7 +35,13 @@ export function Tabs({
       }}
     >
       {tabs.map((t) => (
-        <Tab key={t.value} value={t.value} label={t.label} />
+        <Tab
+          key={t.value}
+          value={t.value}
+          label={t.label}
+          id={tabId(t.value)}
+          aria-controls={panelId(t.value)}
+        />
       ))}
     </MuiTabs>
   );
@@ -47,5 +58,14 @@ export function TabPanel({
   children: ReactNode;
 }) {
   if (value !== current) return null;
-  return <Box sx={{ pt: 2.5 }}>{children}</Box>;
+  return (
+    <Box
+      role="tabpanel"
+      id={panelId(value)}
+      aria-labelledby={tabId(value)}
+      sx={{ pt: 2.5 }}
+    >
+      {children}
+    </Box>
+  );
 }