feat(reader): continue a comic series from the last page

Finishing an issue offered no way onward, so the next one had to be opened from the library.
Resolve the next readable book server-side with one keyset query, offer it on the last page, and
let an opt-in setting cross over on a further page turn. The reader route now remounts on a param
change, without which it would keep rendering the book it was mounted with.

Also cast the compared value in compareSeriesIndexSql: as a bare parameter Postgres could not type
it inside the null test and rejected the statement.

Closes #998

scripts/e2e/suite-registry.mjs

@@ -285,6 +285,25 @@ export const E2E_SUITES = Object.freeze({
       ...SHARED_DB_AND_HELPER_PATHS,
     ],
   },
+  "series-next-book": {
+    id: "series-next-book",
+    name: "Series Next Book",
+    timeout: 60,
+    lane: "full",
+    description: "Series next-readable-book resolution suite",
+    vitestTarget: "test/series-next-book.e2e-spec.ts",
+    junitOutput: `${TEST_RESULTS_DIR}/series-next-book-e2e-junit.xml`,
+    prepareDedicatedDatabase: true,
+    useDedicatedDatabase: true,
+    changedPaths: [
+      "server/src/modules/series/**",
+      "server/test/series-next-book.e2e-spec.ts",
+      "server/test/e2e/authorization-matrix/**",
+      ".github/workflows/e2e-runner.yml",
+      "packages/types/src/series.ts",
+      ...SHARED_DB_AND_HELPER_PATHS,
+    ],
+  },
   "reading-attempts": {
     id: "reading-attempts",
     name: "Reading Attempts",