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/build.rs

@@ -1,7 +1,7 @@
 fn main() {
     // INTERIM: both llama-cpp-sys-2 and whisper-rs-sys statically link
     // their own copy of ggml, so GNU ld / lld see duplicate symbols when
-    // linking the kon binary and its lib-tests. --allow-multiple-definition
+    // linking the magnotia binary and its lib-tests. --allow-multiple-definition
     // makes the linker pick the first definition; safe while both crates
     // pin compatible ggml revisions. Replace with a system-ggml shared-lib
     // setup as a follow-up.
@@ -16,7 +16,7 @@ fn main() {
 
 /// Regression guard for brief item #2 (pre-emptive loopback LLM scope).
 ///
-/// Kon's bundled llama.cpp server and any BYO Ollama install speak HTTP
+/// Magnotia's bundled llama.cpp server and any BYO Ollama install speak HTTP
 /// on `127.0.0.1:*`. If the `connect-src` CSP ever drops those entries,
 /// `fetch()` from the webview to the local LLM silently 404s with an
 /// opaque scope error (Vibe #438 / #487). We keep the current permit