feat(achievements): rebuild the page as a trophy cabinet with hints

Replace the card grid with medals, a showcase, category shelves, a record book and a
detail sheet. Add GET /achievements/hints, which explains how to unlock what is still
locked from the user's own library and reading history, backed by a new page-count
index. Year-Round Reader now reports its months read as progress.

scripts/e2e/suite-registry.mjs

@@ -468,6 +468,25 @@ export const E2E_SUITES = Object.freeze({
       ...SHARED_DB_AND_HELPER_PATHS,
     ],
   },
+  "achievement-hints": {
+    id: "achievement-hints",
+    name: "Achievement Hints",
+    timeout: 60,
+    lane: "full",
+    description: "Achievement how-to-get-it hints: real queries, library scoping, and per-user isolation",
+    vitestTarget: "test/achievement-hints.e2e-spec.ts",
+    junitOutput: `${TEST_RESULTS_DIR}/achievement-hints-e2e-junit.xml`,
+    prepareDedicatedDatabase: true,
+    useDedicatedDatabase: true,
+    changedPaths: [
+      "server/src/modules/achievement/**",
+      "server/test/achievement-hints.e2e-spec.ts",
+      "server/test/e2e/authorization-matrix/**",
+      ".github/workflows/e2e-runner.yml",
+      "packages/types/src/achievement.ts",
+      ...SHARED_DB_AND_HELPER_PATHS,
+    ],
+  },
   "series-next-book": {
     id: "series-next-book",
     name: "Series Next Book",