feat(projects): editable notes with edit stamp + NoteCard bubble component

- author-only note editing (PUT /projects/:id/notes/:noteId, strict schema,
  audit with old/new content); edits stamped via new edited_at column
  (migration 20260612160000) and shown as '· upraveno <datum>'
- note deletion tightened to admin-only server-side (was any projects.edit
  holder via direct API)
- new NoteCard component: chat-bubble note row (initials avatar, wrapping
  header, inline editor, actions in the bubble corner so they don't squeeze
  content on mobile), table-matching edit/delete icons
- Odin project detail carries the edited_at stamp; route-level tests cover
  author-edit, foreign-edit 403, validation, admin-only delete

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

prisma/migrations/20260612160000_project_notes_edited_at/migration.sql

@@ -0,0 +1,3 @@
+-- AlterTable
+ALTER TABLE `project_notes` ADD COLUMN `edited_at` DATETIME(0) NULL;
+