Bump to v0.7.0 — writer tools, NIP-98 uploads, multi-draft, article bookmarks

- NIP-98 HTTP Auth for image uploads with fallback services (void.cat, nostrimg.com)
- Markdown toolbar (bold, italic, heading, link, image, quote, code, list) + Ctrl+B/I/K
- Multi-draft management with draft list, resume, delete, auto-migrate
- Cover image file picker in article meta panel
- Article bookmarks via NIP-51 'a' tags; Notes/Articles tabs in BookmarkView
- Removed Rust upload_file command; dropped reqwest/mime_guess deps
- Upload spinner, draft count badge, empty states

src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "Wrystr",
-  "version": "0.6.1",
+  "version": "0.7.0",
   "identifier": "com.hoornet.wrystr",
   "build": {
     "beforeDevCommand": "npm run dev",