Redesign the quick-action CTAs: two ways in (study deck vs. homework)

Library empty state ("Your icebox")
- Replace the single "Make your first deck" button with two quick-action
  cards: "Create interactive test" (primary, ice-gradient icon + subtle
  accent border) and "Help me with my homework" (glass card, sparkles
  icon). Stacked on phones, side by side from 640px up; both >=44px tall.

/create
- Replace the "Got homework instead of notes?" banner with a two-card mode
  switcher above "1. Add your notes": "Study Deck & Quizzes" (the current
  view — aria-current, accent tint, ice icon) and "Homework Solver" (a
  shortcut to /homework). Icon-on-top tiles on phones, inline rows from
  640px up; glass tokens + backdrop blur in both themes.

Strings
- New keys in both dictionaries: emptyStateCreateDeck, emptyStateHomework,
  actionStudyDeck, actionHomework. Drop the now-unused homework.entry and
  library.makeFirst keys.

Drive-by AA fix (light mode, /create only)
- The "New folder" dashed button and the difficulty blurbs move from
  frost-500 to frost-600 (4.0:1 -> ~6:1). Dark mode is unchanged.

Service worker: freezmo-v8.

Verified: redesign suite 32/32 (stacked/side-by-side layouts, 360/390/1280,
dark+light, en+cs, >=44px targets, both cards navigate, no overflow, axe
contrast), mobile 49/49, i18n 27/27, desktop regression 73/73. Lint + build
clean.

components/LibraryScreen.tsx

@@ -5,7 +5,7 @@ import { useMemo, useRef, useState, useSyncExternalStore } from "react";
 
 import { DeckCard } from "@/components/DeckCard";
 import { FolderBar } from "@/components/FolderBar";
-import { FolderIcon, UploadIcon } from "@/components/icons";
+import { FolderIcon, SnowflakeIcon, SparklesIcon, UploadIcon } from "@/components/icons";
 import { Button, EmptyState } from "@/components/ui";
 import { folderStore, renameFolder } from "@/lib/folders";
 import { useI18n } from "@/lib/i18n";
@@ -224,9 +224,38 @@ export function LibraryScreen() {
         <EmptyState
           title={t("library.noDecks")}
           action={
-            <Link href="/create" className="btn-primary touch-target h-10 px-4 text-sm">
-              {t("library.makeFirst")}
-            </Link>
+            /* Two ways in: build a study deck from notes, or hand over an
+               assignment. Stacked on phones, side by side from 640px up. */
+            <div className="grid w-[min(24rem,calc(100vw_-_3rem))] gap-3 sm:w-[36rem] sm:grid-cols-2">
+              <Link
+                href="/create"
+                className="card card-hover touch-target flex items-center gap-3 border-accent-400/60 p-3.5 text-left sm:p-4"
+              >
+                <span
+                  aria-hidden
+                  className="grad-ice grid size-11 shrink-0 place-items-center rounded-2xl text-[#06111f]"
+                >
+                  <SnowflakeIcon className="size-5" />
+                </span>
+                <span className="min-w-0 text-[14px] font-semibold leading-snug text-[var(--text)]">
+                  {t("emptyStateCreateDeck")}
+                </span>
+              </Link>
+              <Link
+                href="/homework"
+                className="card card-hover touch-target flex items-center gap-3 p-3.5 text-left sm:p-4"
+              >
+                <span
+                  aria-hidden
+                  className="grid size-11 shrink-0 place-items-center rounded-2xl bg-[var(--surface-sunken)] text-[var(--text-muted)]"
+                >
+                  <SparklesIcon className="size-5" />
+                </span>
+                <span className="min-w-0 text-[14px] font-semibold leading-snug text-[var(--text)]">
+                  {t("emptyStateHomework")}
+                </span>
+              </Link>
+            </div>
           }
         >
           {t("library.emptyBody")}