Add game lifecycle management and instance import/export tools (#117)

## Summary by Sourcery

Add centralized game process and instance lifecycle management, shared
cache-aware path resolution, and instance import/export/repair
capabilities across backend and UI.

New Features:
- Track a single running game process in the backend, expose stop-game
control, and emit structured game-exited events with instance and
version context.
- Introduce instance path resolution that supports shared caches for
versions, libraries, and assets, and use it across game start, install,
and version management APIs.
- Add import, export, and repair operations for instances, including
zip-based archive support and automatic recovery of on-disk instances.
- Expose new instance lifecycle and repair APIs to the frontend and wire
them through the client and instance store.
- Add per-instance start/stop controls in the instances view and
instance selection in the bottom bar for launching games.

Enhancements:
- Guard instance operations with per-instance locks and track active
operations such as launch, install, delete, and import/export.
- Improve handling of Microsoft login errors and polling status, with
clearer user feedback and safer interval management.
- Simplify config mutation during shared cache migration and centralize
instance directory resolution in the backend.
- Initialize a game lifecycle listener at app startup to keep UI state
in sync with backend game exit events.

Build:
- Configure the Vite dev server to use a fixed localhost host and port
for the UI dev environment.

2 files changed, 14 insertions, 0 deletions

diff --git a/packages/ui/src/types/bindings/core.ts b/packages/ui/src/types/bindings/core.ts
index 94e3bde..70cf804 100644
--- a/packages/ui/src/types/bindings/core.ts
+++ b/packages/ui/src/types/bindings/core.ts
@@ -11,6 +11,13 @@ export type FileInfo = {
   modified: bigint;
 };
 
+export type GameExitedEvent = {
+  instanceId: string;
+  versionId: string;
+  exitCode: number | null;
+  wasStopped: boolean;
+};
+
 export type GithubRelease = {
   tagName: string;
   name: string;
diff --git a/packages/ui/src/types/bindings/instance.ts b/packages/ui/src/types/bindings/instance.ts
index 2c4f8ae..a8247a9 100644
--- a/packages/ui/src/types/bindings/instance.ts
+++ b/packages/ui/src/types/bindings/instance.ts
@@ -27,6 +27,13 @@ export type InstanceConfig = {
   activeInstanceId: string | null;
 };
 
+export type InstanceRepairResult = {
+  restoredInstances: number;
+  removedStaleEntries: number;
+  createdDefaultActive: boolean;
+  activeInstanceId: string | null;
+};
+
 /**
  * Memory settings override for an instance
  */