fix: react-doctor → 64/100 (Bugs 122, Perf 286, A11y 613, Maint 436)

- CartContext: lazy initializers replace mount-only useEffect
  hydration; remove 8 no-initialize-state warnings
- Toast/AdminSearchInput: React 19 useContext/use + drop
  forwardRef (3 no-react19-deprecated-apis)
- ProductFormModal: lazy initializers + useSyncExternalStore
  for mount; parent adds key=editingProduct.id
- InstallPrompt: useReducer for prompt state (no-cascading-set-state)
- QRScanModal: ref-based latest-callback pattern replaces
  useEffectEvent deps mistake
- OnboardingFlow: functional setState (rerender-functional-setstate)
- UsersPage/StopsCalendar/FeaturesAndStats: lazy initializers
  (rerender-lazy-state-init)
- FAQClientPage: server-side brand settings fetch via getBrandSettingsPublic
  in layout; remove supabase import
- LandingPageWrapper: href='#' → href='#top' (anchor-is-valid)
- TuxedoVideoHero: replace animate-bounce with ease-out-expo
  (no-inline-bounce-easing)
- ProductTableClient: useCallback for handleDeleted
  (jsx-no-new-function-as-prop)
- excel-parser: pre-compile delimiter regexes (js-hoist-regexp)
- water-log/settings: Promise.all for parallel DB calls
  (async-parallel)
- ToastNotification: extract toast store to separate file
  (only-export-components)
- WholesaleClient: inline <WholesaleIcon/> instead of hoisting to
  const (rendering-hoist-jsx)

src/actions/water-log/field.ts

@@ -128,28 +128,33 @@ await getSession();  // Validate format first (cheap, no DB).
     return { success: false, error: "Invalid PIN" };
   }
 
-  // Create a session in the user's brand context.
-  const sessionId = await withBrand(match.brandId, async (db) => {
-    const expiresAt = new Date(
-      Date.now() + FIELD_SESSION_HOURS * 60 * 60 * 1000,
-    );
-    const [row] = await db
-      .insert(waterSessions)
-      .values({
-        irrigatorId: match.id,
-        expiresAt,
-      })
-      .returning({ id: waterSessions.id });
-    if (!row) throw new Error("Failed to create session");
-    // Bump last_used_at for "I haven't seen this person in a while" UX
-    await db
-      .update(waterIrrigators)
-      .set({ lastUsedAt: new Date() })
-      .where(eq(waterIrrigators.id, match.id));
-    return row.id;
-  });
-
-  const cookieStore = await cookies();
+  // Create a session in the user's brand context. The session insert
+  // and the last_used_at bump are independent writes — fire them in
+  // parallel and wait on both before returning.
+  const [sessionId, cookieStore] = await Promise.all([
+    withBrand(match.brandId, async (db) => {
+      const expiresAt = new Date(
+        Date.now() + FIELD_SESSION_HOURS * 60 * 60 * 1000,
+      );
+      const [insertResult] = await Promise.all([
+        db
+          .insert(waterSessions)
+          .values({
+            irrigatorId: match.id,
+            expiresAt,
+          })
+          .returning({ id: waterSessions.id }),
+        db
+          .update(waterIrrigators)
+          .set({ lastUsedAt: new Date() })
+          .where(eq(waterIrrigators.id, match.id)),
+      ]);
+      const row = insertResult[0];
+      if (!row) throw new Error("Failed to create session");
+      return row.id;
+    }),
+    cookies(),
+  ]);
   cookieStore.set("wl_session", sessionId, {
     httpOnly: true,
     secure: process.env.NODE_ENV === "production",