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/FocusTimer.svelte

@@ -5,7 +5,7 @@
   // centre. Completion plays a gentle chime, flashes a success ring
   // for 3 s, then disappears. Cancel button appears on hover.
   //
-  // Mounted once in +layout.svelte. Listens for `kon:start-timer`
+  // Mounted once in +layout.svelte. Listens for `magnotia:start-timer`
   // events from anywhere in the app (e.g. MicroSteps) and delegates
   // to the focus-timer store.
   //
@@ -63,7 +63,7 @@
     return "var(--color-accent)";
   });
 
-  // Event handler: start a timer when any component fires `kon:start-timer`.
+  // Event handler: start a timer when any component fires `magnotia:start-timer`.
   // Payload shape from MicroSteps.svelte and task row buttons:
   //   { taskId?: string, seconds: number, label?: string }
   function handleStartEvent(evt: Event) {
@@ -77,13 +77,13 @@
   }
 
   onMount(() => {
-    window.addEventListener("kon:start-timer", handleStartEvent);
+    window.addEventListener("magnotia:start-timer", handleStartEvent);
     // Rehydrate any in-flight timer that survived a window close.
     focusTimer.rehydrate();
   });
 
   onDestroy(() => {
-    window.removeEventListener("kon:start-timer", handleStartEvent);
+    window.removeEventListener("magnotia:start-timer", handleStartEvent);
   });
 
   function handleCancel() {