add journaling feature: categories, tags, attachments, calendar, and multi-select emotions

Adds an 8th development stage that lets users keep a free-form journal alongside
habit tracking, reusing the existing Google OAuth/DB/PWA infrastructure instead
of a separate project. Users organize entries into custom categories, filter by
a month calendar with day-detail drill-down, attach photos/videos (served via an
authenticated route, never /static), tag entries, and pick multiple emotions per
entry from a curated 9-option set. Includes a global journal prompt bank for
lightweight guided journaling.

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

app/static/service-worker.js

@@ -1,9 +1,10 @@
-const CACHE_NAME = "habit-tracker-v4";
+const CACHE_NAME = "habit-tracker-v5";
 const APP_SHELL = [
   "/static/css/style.css",
   "/static/js/app.js",
   "/static/js/push-register.js",
   "/static/js/habit-reorder.js",
+  "/static/js/journal-category-reorder.js",
   "/static/js/vendor/htmx.min.js",
   "/static/js/vendor/alpine.min.js",
   "/static/js/vendor/sortable.min.js",