note title equip: DON/DOFF buttons outside top-left corner; User.active_title FK; don/doff views; greeting updated via JS — TDD

- lyric/models.py: active_title = ForeignKey('drama.Note', null=True, SET_NULL)
- lyric migration 0020_add_active_title
- billboard/views.py: don_title + doff_title views; is_equipped per note_item context
- billboard/urls.py: note/<slug>/don + note/<slug>/doff routes
- _navbar.html: id_greeting_name span; shows active_title.slug|capfirst when set
- my_notes.html: .note-don-doff buttons (DON/DOFF, × when disabled); data-don-url/doff-url/title attrs
- note-page.js: _bindDonDoff() — DON POST sets greeting + swaps btn state; DOFF restores Earthman
- _note.scss: .note-don-doff position:absolute left:-1rem top:0; flex-direction:column gap:1.25rem
- ITs: NoteEquipTitleViewTest (5 tests); UserModelTest.test_active_title_* (3 tests)
- FT: NoteEquipTitleTest.test_don_equips_title_greeting_and_doff_restores

Code architected by Disco DeDisco <discodedisco@outlook.com>
Git commit message Co-Authored-By:
Claude Sonnet 4.6 <noreply@anthropic.com>

src/apps/billboard/urls.py

@@ -9,6 +9,8 @@ urlpatterns = [
     path("toggle-applets", views.toggle_billboard_applets, name="toggle_applets"),
     path("my-notes/", views.my_notes, name="my_notes"),
     path("note/<slug:slug>/set-palette", views.note_set_palette, name="note_set_palette"),
+    path("note/<slug:slug>/don", views.don_title, name="don_title"),
+    path("note/<slug:slug>/doff", views.doff_title, name="doff_title"),
     path("room/<uuid:room_id>/scroll/", views.room_scroll, name="scroll"),
     path("room/<uuid:room_id>/scroll-position/", views.save_scroll_position, name="save_scroll_position"),
 ]