fix: resolve remaining QA issues -- editor features, masking, persistence, Playwright tests

Phase 1 quick fixes:
- Add isInputFocused() guard to Cmd+A/D/T/J shortcuts (P1-7)
- Add Go Home button to tool-not-found page (P2-30)
- Fix hardcoded "Import from Library" string in file library modal (P2-28)
- Fix TeamEntry.id type from number to string to match API (P2-6)
- Add eye toggle to confirm password field (P2-10)
- Add Apply/Cancel buttons to Free Transform options bar (P2-14)

Phase 2 state fixes:
- Add sessionStorage persistence to pipeline store (P1-26)
- Fix Free Transform 0 dimensions by falling back to selection bounds (P1-6)

Phase 3 editor features:
- Constrain brush/eraser drawing within active selection bounds (P1-5)
- Add feather radius control to selection options (P2-21)
- Add flow control slider to brush options (P2-22)
- Add brush/block mode selector to eraser options (P2-23)
- Add estimated file size display to export dialog (P2-18)

Phase 4:
- Add Playwright e2e tests for key fixes (404 page, routing, pipeline persistence, export dialog)

apps/web/src/pages/fullscreen-grid-page.tsx

@@ -4,7 +4,9 @@ import { Eye, EyeOff, FileImage, LayoutGrid, List, Search } from "lucide-react";
 import { useEffect, useMemo, useState } from "react";
 import { Link, useNavigate } from "react-router-dom";
 import { OtterLogo } from "@/components/common/otter-logo";
+import { MobileBottomNav } from "@/components/layout/mobile-bottom-nav";
 import { useTranslation } from "@/contexts/i18n-context";
+import { useMobile } from "@/hooks/use-mobile";
 import { track } from "@/lib/analytics";
 import { apiGet } from "@/lib/api";
 import { ICON_MAP } from "@/lib/icon-map";
@@ -14,6 +16,7 @@ import { useFeaturesStore } from "@/stores/features-store";
 
 export function FullscreenGridPage() {
   const { t } = useTranslation();
+  const isMobile = useMobile();
   const [search, setSearch] = useState("");
   const [showDetails, setShowDetails] = useState(true);
   const navigate = useNavigate();
@@ -79,7 +82,7 @@ export function FullscreenGridPage() {
   const activeCategories = CATEGORIES.filter((cat) => groupedTools.has(cat.id));
 
   return (
-    <div className="min-h-screen bg-background text-foreground">
+    <div className={cn("min-h-screen bg-background text-foreground", isMobile && "pb-20")}>
       {/* Top bar */}
       <header className="sticky top-0 z-30 bg-background/95 backdrop-blur-sm border-b border-border">
         <div className="max-w-7xl mx-auto px-4 sm:px-6 py-3 flex items-center gap-4">
@@ -154,6 +157,7 @@ export function FullscreenGridPage() {
           </div>
         )}
       </main>
+      {isMobile && <MobileBottomNav />}
     </div>
   );
 }