chore: rebrand from Kon/Corbie to Magnotia

Replace all instances of the legacy product names "Kon" and "Corbie" with
"Magnotia" across user-facing copy, code identifiers, package names, bundle
ids, file paths, and documentation. Preserves the unrelated "konsole" (KDE
terminal) reference and the parent CORBEL company name.

- Renames 10 Rust crates (kon-* → magnotia-*) and the tauri binary
- Updates package.json, tauri.conf.json (productName + identifier)
- Renames CSS classes (kon-rh-* → magnotia-rh-*) and animations
- Renames brand and roadmap docs
- Regenerates Cargo.lock and package-lock.json

Verified: svelte-check passes; pure-rust crates compile under new names.

src/lib/components/HotkeyRecorder.svelte

@@ -26,7 +26,7 @@
   ]);
 
   // Map KeyboardEvent.code (physical key, layout-independent, shift-independent)
-  // to the unshifted name the kon-hotkey evdev parser understands. Browser
+  // to the unshifted name the magnotia-hotkey evdev parser understands. Browser
   // e.key returns "+" for Shift+Equal — parser wants "=". Same for | → \, etc.
   const codeToParserKey: Record<string, string> = {
     Equal: "=", Minus: "-",