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/routes/+layout.svelte

@@ -42,7 +42,7 @@
   const prefs = getPreferences();
   const tauriRuntimeAvailable = hasTauriRuntime();
 
-  // On Linux Kon uses native KWin/Mutter decorations (see
+  // On Linux Magnotia uses native KWin/Mutter decorations (see
   // src-tauri/tauri.linux.conf.json and windows.rs). Frameless custom
   // chrome stays for macOS and Windows. Default to false so Linux users
   // don't see a flash of custom titlebar before loadOsInfo resolves.
@@ -68,7 +68,7 @@
   });
 
   // Global hotkey registration — dual backend
-  // Wayland: evdev via kon-hotkey crate (works without display server)
+  // Wayland: evdev via magnotia-hotkey crate (works without display server)
   // X11/macOS/Windows: tauri-plugin-global-shortcut (native)
   let registeredHotkey = null;
   let hotkeyBackend = $state("unknown"); // "evdev" | "tauri" | "unavailable"
@@ -123,7 +123,7 @@
         await mod.register(hotkey, () => {
           if (page.current !== "dictation") page.current = "dictation";
           requestAnimationFrame(() => {
-            window.dispatchEvent(new CustomEvent("kon:toggle-recording"));
+            window.dispatchEvent(new CustomEvent("magnotia:toggle-recording"));
           });
         });
         registeredHotkey = hotkey;
@@ -159,13 +159,13 @@
   async function setupEvdevListener() {
     if (!tauriRuntimeAvailable) return;
     const { listen } = await import("@tauri-apps/api/event");
-    unlistenEvdev = await listen("kon:hotkey-pressed", () => {
+    unlistenEvdev = await listen("magnotia:hotkey-pressed", () => {
       const now = Date.now();
       if (now - lastHotkeyAtMs < HOTKEY_DEBOUNCE_MS) return;
       lastHotkeyAtMs = now;
       if (page.current !== "dictation") page.current = "dictation";
       requestAnimationFrame(() => {
-        window.dispatchEvent(new CustomEvent("kon:toggle-recording"));
+        window.dispatchEvent(new CustomEvent("magnotia:toggle-recording"));
       });
     });
   }
@@ -217,7 +217,7 @@
   let unlistenWindDown = null;
   async function setupWindDownListener() {
     if (!tauriRuntimeAvailable) return;
-    unlistenWindDown = await listen("kon:open-wind-down", () => {
+    unlistenWindDown = await listen("magnotia:open-wind-down", () => {
       page.current = "shutdown";
     });
   }
@@ -325,7 +325,7 @@
     invoke("check_for_update")
       .then((version) => {
         if (version) {
-          toasts.info(`Kon ${version} is available. Download and restart to update.`);
+          toasts.info(`Magnotia ${version} is available. Download and restart to update.`);
         }
       })
       .catch(() => { /* update check failure must not affect the app */ });
@@ -442,7 +442,7 @@
      in the bottom-right of the viewport. (Day 3 of the upgrade plan) -->
 <ToastViewport />
 
-<!-- Global focus-timer overlay. Renders nothing until a `kon:start-timer`
+<!-- Global focus-timer overlay. Renders nothing until a `magnotia:start-timer`
      event fires; then pins a shrinking colour ring to the top-right.
      Phase 1 of the 2026-04-23 feature-complete roadmap — closes the
      visual-time-representation gap from docs/brief/feature-set.md and