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/WipTaskList.svelte

@@ -5,7 +5,7 @@
   import { ChevronDown, ChevronRight, Timer } from 'lucide-svelte';
 
   function startFocusTimer(task: { id: string; text: string }) {
-    window.dispatchEvent(new CustomEvent('kon:start-timer', {
+    window.dispatchEvent(new CustomEvent('magnotia:start-timer', {
       detail: { taskId: task.id, seconds: 300, label: task.text }
     }));
   }