refactor(ui): full rewrite instance and code struct (#129)

## Summary by Sourcery

Refactor the UI to modernize effect handling, routing, and legacy APIs
while adding a reusable alert dialog component and cleaning up obsolete
stores.

New Features:
- Introduce a shared SaturnEffect context via ParticleBackground so
pages can access the effect without relying on global window APIs.
- Add a Base UI–powered alert dialog component for consistent
confirmation and warning flows across the app.
- Define a central router configuration module with instance routes to
standardize page wiring.

Bug Fixes:
- Ensure SaturnEffect nullish checks are handled safely when forwarding
pointer and touch events from the home view.

Enhancements:
- Rewrite ParticleBackground to manage its own SaturnEffect lifecycle
via React state and context instead of global accessors.
- Update the home view to use the SaturnEffect hook, simplify
pointer/touch handlers, and remove legacy game and release store usage.
- Refine layout and accessibility attributes for various form field and
label components, including field grouping and error rendering keys.
- Simplify sidebar navigation and adjust the user dropdown trigger to
work with the updated dropdown menu API.
- Wrap the root outlet for the home route with ParticleBackground only
on the index path to limit the effect to the intended view.
- Clean up imports and code style in radio group and other UI primitives
for consistency.

Chores:
- Remove deprecated UI stores and utility modules that are no longer
used with the new architecture.
- Add changeset entries documenting the Saturn effect refactor,
ParticleBackground rewrite, and removal of legacy store code.

1 files changed, 10 insertions, 13 deletions

diff --git a/packages/ui/src/models/instance.ts b/packages/ui/src/models/instance.ts
index e1eb7c1..8c108c1 100644
--- a/packages/ui/src/models/instance.ts
+++ b/packages/ui/src/models/instance.ts
@@ -20,13 +20,16 @@ interface InstanceState {
   activeInstance: Instance | null;
 
   refresh: () => Promise<void>;
-  create: (name: string) => Promise<Instance | null>;
+  create: (name: string) => Promise<Instance>;
   delete: (id: string) => Promise<void>;
   update: (instance: Instance) => Promise<void>;
   setActiveInstance: (instance: Instance) => Promise<void>;
   duplicate: (id: string, newName: string) => Promise<Instance | null>;
   exportArchive: (id: string, archivePath: string) => Promise<void>;
-  importArchive: (archivePath: string, newName?: string) => Promise<Instance | null>;
+  importArchive: (
+    archivePath: string,
+    newName?: string,
+  ) => Promise<Instance | null>;
   repair: () => Promise<void>;
   get: (id: string) => Promise<Instance | null>;
 }
@@ -61,17 +64,11 @@ export const useInstanceStore = create<InstanceState>((set, get) => ({
 
   create: async (name) => {
     const { refresh } = get();
-    try {
-      const instance = await createInstance(name);
-      await setActiveInstanceCommand(instance.id);
-      await refresh();
-      toast.success(`Instance "${name}" created successfully`);
-      return instance;
-    } catch (e) {
-      console.error("Failed to create instance:", e);
-      toast.error(String(e));
-      return null;
-    }
+    const instance = await createInstance(name);
+    await setActiveInstanceCommand(instance.id);
+    await refresh();
+    toast.success(`Instance "${name}" created successfully`);
+    return instance;
   },
 
   delete: async (id) => {