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/commands/models.rs

@@ -5,14 +5,14 @@ use tauri::Emitter;
 
 use crate::commands::security::ensure_main_window;
 use crate::AppState;
-use kon_core::constants::WHISPER_SAMPLE_RATE;
-use kon_core::hardware::{self, CpuFeatures};
-use kon_core::model_registry::{self, Engine, LanguageSupport, ModelEntry};
-use kon_core::types::{AudioSamples, ModelId, TranscriptionOptions};
+use magnotia_core::constants::WHISPER_SAMPLE_RATE;
+use magnotia_core::hardware::{self, CpuFeatures};
+use magnotia_core::model_registry::{self, Engine, LanguageSupport, ModelEntry};
+use magnotia_core::types::{AudioSamples, ModelId, TranscriptionOptions};
 #[cfg(feature = "whisper")]
-use kon_transcription::load_whisper;
-use kon_transcription::model_manager;
-use kon_transcription::{load_parakeet, LocalEngine, Transcriber};
+use magnotia_transcription::load_whisper;
+use magnotia_transcription::model_manager;
+use magnotia_transcription::{load_parakeet, LocalEngine, Transcriber};
 
 /// Map legacy size strings to ModelId.
 fn whisper_model_id(size: &str) -> ModelId {
@@ -94,7 +94,7 @@ pub fn load_model_from_disk(model_id: &ModelId) -> Result<Box<dyn Transcriber +
         }
         #[cfg(not(feature = "whisper"))]
         Engine::Whisper => Err(format!(
-            "Whisper backend not compiled in this build (kon built without the \"whisper\" feature); \
+            "Whisper backend not compiled in this build (magnotia built without the \"whisper\" feature); \
              cannot load {model_id}"
         )),
         Engine::Parakeet => {