v1.1.3 - Line numbers scroll fix, source mode undo/redo, Ctrl+K links, hard break fixes

- Line numbers scroll fix: source mode line numbers now scroll properly with content
- Source mode undo/redo: custom history stack for Ctrl+Z / Ctrl+Shift+Z in markdown mode
- Shift+Enter hard breaks in source mode (inserts trailing spaces + newline)
- Ctrl+K link shortcut: global keybinding for inserting/editing links
- Link modal improvements: auto-prepends https://, preserves selection range
- Hard break serialization fix: trailing spaces preserved in markdown output
- Drag prevention: prevents native text drag (copy-instead-of-move issue in Tauri webview)

src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "../node_modules/@tauri-apps/cli/config.schema.json",
   "productName": "HelixNotes",
-  "version": "1.1.2",
+  "version": "1.1.3",
   "identifier": "com.helixnotes.app",
   "build": {
     "frontendDist": "../build",