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-tauri/src/tray.rs

@@ -4,7 +4,7 @@ use tauri::tray::TrayIconBuilder;
 use tauri::{Emitter, Manager};
 
 pub fn setup(app: &tauri::App) -> Result<(), Box<dyn std::error::Error>> {
-    let show = MenuItemBuilder::with_id("show", "Show Kon").build(app)?;
+    let show = MenuItemBuilder::with_id("show", "Show Magnotia").build(app)?;
     let status = MenuItemBuilder::with_id("status", "Ready")
         .enabled(false)
         .build(app)?;
@@ -32,7 +32,7 @@ pub fn setup(app: &tauri::App) -> Result<(), Box<dyn std::error::Error>> {
 
     let _tray = TrayIconBuilder::new()
         .icon(icon)
-        .tooltip("Kon — Ready")
+        .tooltip("Magnotia — Ready")
         .menu(&menu)
         .on_menu_event(move |app, event| match event.id().as_ref() {
             "show" => {
@@ -48,7 +48,7 @@ pub fn setup(app: &tauri::App) -> Result<(), Box<dyn std::error::Error>> {
                 }
                 // The frontend layout listens for this event and routes
                 // to the Phase 5 wind-down page.
-                let _ = app.emit("kon:open-wind-down", ());
+                let _ = app.emit("magnotia:open-wind-down", ());
             }
             "quit" => {
                 app.exit(0);