Show reference-data update time, location filter UI, and tile fixes

- Status gains reference_updated_at (sourced from reference.db's file
  mtime, so it needs no separate persisted state) and the sidebar's
  "Your library" panel shows it as a relative "Updated Xh ago" stamp
  that self-refreshes every minute.
- Add a Location field to the Library tab's filters panel, wired to the
  new LibraryFilter.location.
- Bump every font-size in the stylesheet up one step for a slightly
  larger, easier-to-read UI overall.
- Fix the library/deck tile view's +/- quantity overlay permanently
  covering the card art's own printed mana cost (top-right corner) —
  it now only fades in on hover/focus, like the other row actions.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/views/LibraryBrowser.tsx

@@ -31,6 +31,7 @@ export function LibraryBrowser() {
   const [subtype, setSubtype] = useState("");
   const [keyword, setKeyword] = useState("");
   const [inDeck, setInDeck] = useState<number | "">("");
+  const [location, setLocation] = useState("");
 
   const [decks, setDecks] = useState<Deck[]>([]);
   const [rows, setRows] = useState<LibraryCard[]>([]);
@@ -59,12 +60,25 @@ export function LibraryBrowser() {
       subtypes: splitCsv(subtype),
       keywords: splitCsv(keyword),
       in_deck: inDeck === "" ? null : Number(inDeck),
+      location: location.trim() || null,
     };
     const t = setTimeout(() => {
       api.searchLibrary(filter).then(setRows).catch(() => setRows([]));
     }, 120);
     return () => clearTimeout(t);
-  }, [text, commander, colorsInclude, cmcMin, cmcMax, type, subtype, keyword, inDeck, refreshKey]);
+  }, [
+    text,
+    commander,
+    colorsInclude,
+    cmcMin,
+    cmcMax,
+    type,
+    subtype,
+    keyword,
+    inDeck,
+    location,
+    refreshKey,
+  ]);
 
   async function adjust(oracleId: string, delta: number) {
     const qty = await api.addOwned(oracleId, delta);
@@ -261,6 +275,14 @@ export function LibraryBrowser() {
             ))}
           </select>
         </div>
+        <div className="field">
+          <label>Location</label>
+          <input
+            value={location}
+            onChange={(e) => setLocation(e.target.value)}
+            placeholder="e.g. Box 1"
+          />
+        </div>
       </div>
 
       {rows.length === 0 ? (