app: Classes binder + Mind Dump — v0.5.0

Two new tabs in the Studio Notebook:

- 📚 Classes: a binder for courses, workshops, books, and video series.
  Each class has a subject, source, link, status (taking / want / done),
  a what-it's-about note, photos, handout files, and dated pages of
  class notes that can be edited in place.
- 💭 Mind Dump: idea capture filed by category (things to make — with a
  medium: clay / wood / silver / metal / mixed — marketing, packaging,
  display & booth, shop & site, other) with spark / trying / did it /
  parked status, sketch photos, one-tap 'make it a to-do', and filters.
  The Today jot box gains a 💭 idea chip; those land as 'unsorted' to
  file later.

Schema: Course, CoursePage, Idea (additive; prisma db push at boot).
Files tab now labels attachments that belong to a class.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

app/package.json

@@ -1,6 +1,6 @@
 {
   "name": "bms-backbone",
-  "version": "0.4.0",
+  "version": "0.5.0",
   "private": true,
   "type": "module",
   "scripts": {