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/MicroSteps.svelte

@@ -58,7 +58,7 @@
       // is completed in that window, a gentle "still with that one?"
       // nudge fires.
       if (typeof window !== 'undefined') {
-        window.dispatchEvent(new CustomEvent('kon:microstep-generated', {
+        window.dispatchEvent(new CustomEvent('magnotia:microstep-generated', {
           detail: { parentTaskId },
         }));
       }
@@ -78,7 +78,7 @@
       // micro-step-idle timer for this parent task — the breakdown
       // is demonstrably getting worked, no nudge needed.
       if (typeof window !== 'undefined') {
-        window.dispatchEvent(new CustomEvent('kon:step-completed', {
+        window.dispatchEvent(new CustomEvent('magnotia:step-completed', {
           detail: { id: subtaskId, parentTaskId },
         }));
       }
@@ -86,7 +86,7 @@
   }
 
   function startTimer(subtaskId: string) {
-    window.dispatchEvent(new CustomEvent('kon:start-timer', {
+    window.dispatchEvent(new CustomEvent('magnotia:start-timer', {
       detail: { taskId: subtaskId, seconds: 120 }
     }));
   }