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/core/src/recommendation.rs

@@ -184,7 +184,7 @@ mod tests {
     fn parakeet_is_top_recommendation_when_hardware_supports_it() {
         // Any machine that fits Parakeet in RAM should see it ranked first —
         // Parakeet-TDT is English-only but beats Whisper on English at lower
-        // latency, so it's Kon's default recommendation when eligible.
+        // latency, so it's Magnotia's default recommendation when eligible.
         // (Users on non-English languages adjust manually — handled at the
         // settings-UI level, not at the scoring level for now.)
         let profile = profile_with_ram(Megabytes(16384));