v2.2.0 — Canvas, PDF & Drawing Open as Tabs

Canvas, PDF, and drawing files now open as real tabs instead of overlays floating over your last note — and canvas images actually render.

🗂️ Tabs

• Canvas / PDF / drawing open as first-class tabs: they show in the tab strip, the title bar shows their name, the right tab is highlighted, and the active tab drives everything.
• Previously they opened as overlays while the underlying .md stayed "active" — so the title showed the note, the wrong tab was highlighted, and Ctrl+Shift+P exported the note instead of what was open.
• The canvas renders in the editor area now, so clicking another tab switches away from it.
• PDF export, the lines/chars/word-count status items, and the Edit/View/Source toggle are hidden/guarded for non-markdown tabs.

🖼️ Canvas

• Images (png/jpg/etc.) now render in the canvas. They loaded via file://, which the Tauri/WebKitGTK webview blocks; now they load via the same data: URL path note images use.

📎 Other

• Bumped version to 2.2.0 across package.json, Cargo.toml, tauri.conf.json, and Cargo.lock
• Note: PDF and drawing are still full-screen views (exit via their close button); the same in-editor treatment as canvas is a possible follow-up.