Merge Bitcoin categories into one; rename Self-Hosted Apps to Personal Apps

- One "Bitcoin" category: the service catalog distinguishes bitcoin-base
  from bitcoin-apps, which surfaced as two sidebar menus and two tile
  sections. The Hub now normalizes both into a single "Bitcoin" category
  (nav item with combined count, one tile section). CATEGORY_ALIASES in
  constants.js maps the catalog keys; server config sends one
  ("bitcoin", "Bitcoin") entry and the node role allowlist is updated
  to match. The nix catalog is unchanged.
- "Self-Hosted Apps" is now "Personal Apps" — every service here is
  self-hosted, so the label added no distinction.

app/sovran_systemsos_web/static/js/tiles.js

@@ -25,6 +25,7 @@ function buildTiles(services, categoryLabels) {
       continue;
     }
     var cat = svc.category || "other";
+    if (CATEGORY_ALIASES[cat]) cat = CATEGORY_ALIASES[cat];
     if (!grouped[cat]) grouped[cat] = [];
     grouped[cat].push(svc);
   }