Notification titles and messages are hardcoded English (~36 sites)

Summary

~36 Notification::success/info/error/warning(...) calls across ui_core and ui_level_editor use hardcoded English title strings. These show up as toast notifications to the user and should be translatable via t!().

Affected locations

crates/editor/ui_core/src/:

• root.rs: Notification::info("Dev"), Notification::info("Build Info"), Notification::info("Dev").message("Asset reload not yet implemented.")
• app/render.rs: Notification::info("Project Loaded")
• app/event_handlers.rs: Notification::success("Rust Analyzer Ready"), Notification::error("Analyzer Error"), Notification::success("Code Intelligence Ready")
• app/constructors.rs: Notification::info("Build"), Notification::info("Run")

crates/editor/ui_level_editor/src/:

• level_editor/ui/viewport/helio_viewport.rs: "Adding to Scene", "Added to Scene", "Placement Failed", "Mesh Load Failed"
• level_editor/ui/viewport/game_viewport.rs: "Play In Editor"
• level_editor/ui/toolbar/mod.rs: "Save as Default Level" (success/error variants)
• level_editor/ui/toolbar/build_core.rs: "No project open — open a project first.", "Cleaning build artifacts...", "Build succeeded.", "Starting check...", "Check passed.", "Updating dependencies...", "Dependencies updated.", "Starting build..."
• level_editor/ui/panel.rs: "Play In Editor build failed", "Play In Editor", "Building game..."

Suggested fix

Replace each hardcoded title/message with t!("Notification.Title.Name") and add the corresponding keys to each crate's locales/en.yml.