Import historical ratings from arbitrary URLs as a background job

The Ratings page gains an "Import ratings" form: paste URLs (one per
line), choose a verdict and an optional note. Rows land in the new
rating_imports table and the new import-ratings job (same systemd job
template as the rest of the catalogue) canonicalizes each URL, reuses or
fetches + extracts the article, embeds it with Voyage when enabled, and
appends an explicit rating event with source "import". Per-URL status
shows on the Ratings page; the job page's journal is the live log.

Imported articles have no entry row (best_entry_id NULL, feed "Imported")
and no sources, so they act as rated neighbours without touching the
feed prior. The CLI's rating-event construction moves to rate::record_explicit
and the dashboard job start path is shared as jobs::start_job.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QVPagF6jfDv78CC5Jv2wp4

src/web/static/app.js

@@ -73,7 +73,8 @@ document.addEventListener("submit", (event) => {
 document.querySelectorAll("details[id]").forEach((details) => {
   try {
     const key = "details:" + details.id;
-    details.open = localStorage.getItem(key) === "open";
+    const saved = localStorage.getItem(key);
+    if (saved === "open" || saved === "closed") details.open = saved === "open";
     details.addEventListener("toggle", () => localStorage.setItem(key, details.open ? "open" : "closed"));
   } catch (_) {}
 });