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.

crates/cloud-providers/src/keystore.rs

@@ -1,13 +1,13 @@
 use std::collections::HashMap;
 use std::sync::{Mutex, OnceLock};
 
-/// Store an API key in Kon's process-local keystore.
+/// Store an API key in Magnotia's process-local keystore.
 ///
 /// Keys are held in memory for the lifetime of the process and are lost on
 /// exit. This avoids the undefined behaviour of mutating process environment
 /// variables from arbitrary threads while keeping the public API safe.
 ///
-/// `retrieve_api_key` still falls back to `KON_API_KEY_<PROVIDER>` environment
+/// `retrieve_api_key` still falls back to `MAGNOTIA_API_KEY_<PROVIDER>` environment
 /// variables so externally injected secrets continue to work.
 ///
 /// TODO: Replace with the `keyring` crate (or platform-native credential
@@ -19,10 +19,10 @@ pub fn store_api_key(provider: &str, key: &str) {
         .insert(provider_env_key(provider), key.to_string());
 }
 
-/// Retrieve an API key from Kon's process-local keystore.
+/// Retrieve an API key from Magnotia's process-local keystore.
 ///
 /// Returns a previously stored in-memory key when present, otherwise falls
-/// back to the read-only `KON_API_KEY_<PROVIDER>` environment variable so
+/// back to the read-only `MAGNOTIA_API_KEY_<PROVIDER>` environment variable so
 /// operator-supplied secrets still work.
 pub fn retrieve_api_key(provider: &str) -> Option<String> {
     let env_key = provider_env_key(provider);
@@ -40,7 +40,7 @@ fn api_key_store() -> &'static Mutex<HashMap<String, String>> {
 }
 
 fn provider_env_key(provider: &str) -> String {
-    format!("KON_API_KEY_{}", provider.to_uppercase())
+    format!("MAGNOTIA_API_KEY_{}", provider.to_uppercase())
 }
 
 #[cfg(test)]