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/types/app.ts

@@ -99,7 +99,7 @@ export interface SettingsState {
   ritualsMorningTime: string;
   ritualsEvening: boolean;
   /**
-   * Phase 5: register Corbie as a login-time autostart entry. The
+   * Phase 5: register Magnotia as a login-time autostart entry. The
    * actual OS-level state lives in `tauri-plugin-autostart`; this
    * flag mirrors it so the Settings UI can render without a round-trip
    * on every mount.