chore(ui): refactor workspace to monorepo (#70)

## Summary by Sourcery

Refactor the UI project structure into a pnpm monorepo packages layout
and align tooling and automation with the new paths.

Enhancements:
- Reorganize the UI app from the root ui directory into packages/ui
within a pnpm workspace.
- Update pnpm workspace configuration to include all packages under
packages/*.
- Adjust paths in changeset configuration so the @dropout/ui package
resolves from packages/ui.

Build:
- Update pre-commit configuration paths and arguments to reflect the new
UI location and normalize hook argument formatting.
- Update Dependabot configuration so npm updates target /packages/ui
instead of /ui.

CI:
- Update GitHub Actions workflows to watch packages/** instead of ui/**
and to run frontend tasks from packages/ui.
- Update pnpm cache dependency paths in workflows to use the root
pnpm-lock.yaml.
- Simplify frontend install steps in test workflows to run from the
repository root.

Chores:
- Add a new index.html under packages/ui and remove the old
ui/index.html to match the new project layout.

1 files changed, 109 insertions, 0 deletions

diff --git a/packages/ui/src/stores/instances.svelte.ts b/packages/ui/src/stores/instances.svelte.ts
new file mode 100644
index 0000000..f4ac4e9
--- /dev/null
+++ b/packages/ui/src/stores/instances.svelte.ts
@@ -0,0 +1,109 @@
+import { invoke } from "@tauri-apps/api/core";
+import type { Instance } from "../types";
+import { uiState } from "./ui.svelte";
+
+export class InstancesState {
+  instances = $state<Instance[]>([]);
+  activeInstanceId = $state<string | null>(null);
+  get activeInstance(): Instance | null {
+    if (!this.activeInstanceId) return null;
+    return this.instances.find((i) => i.id === this.activeInstanceId) || null;
+  }
+
+  async loadInstances() {
+    try {
+      this.instances = await invoke<Instance[]>("list_instances");
+      const active = await invoke<Instance | null>("get_active_instance");
+      if (active) {
+        this.activeInstanceId = active.id;
+      } else if (this.instances.length > 0) {
+        // If no active instance but instances exist, set the first one as active
+        await this.setActiveInstance(this.instances[0].id);
+      }
+    } catch (e) {
+      console.error("Failed to load instances:", e);
+      uiState.setStatus("Error loading instances: " + e);
+    }
+  }
+
+  async createInstance(name: string): Promise<Instance | null> {
+    try {
+      const instance = await invoke<Instance>("create_instance", { name });
+      await this.loadInstances();
+      uiState.setStatus(`Instance "${name}" created successfully`);
+      return instance;
+    } catch (e) {
+      console.error("Failed to create instance:", e);
+      uiState.setStatus("Error creating instance: " + e);
+      return null;
+    }
+  }
+
+  async deleteInstance(id: string) {
+    try {
+      await invoke("delete_instance", { instanceId: id });
+      await this.loadInstances();
+      // If deleted instance was active, set another as active
+      if (this.activeInstanceId === id) {
+        if (this.instances.length > 0) {
+          await this.setActiveInstance(this.instances[0].id);
+        } else {
+          this.activeInstanceId = null;
+        }
+      }
+      uiState.setStatus("Instance deleted successfully");
+    } catch (e) {
+      console.error("Failed to delete instance:", e);
+      uiState.setStatus("Error deleting instance: " + e);
+    }
+  }
+
+  async updateInstance(instance: Instance) {
+    try {
+      await invoke("update_instance", { instance });
+      await this.loadInstances();
+      uiState.setStatus("Instance updated successfully");
+    } catch (e) {
+      console.error("Failed to update instance:", e);
+      uiState.setStatus("Error updating instance: " + e);
+    }
+  }
+
+  async setActiveInstance(id: string) {
+    try {
+      await invoke("set_active_instance", { instanceId: id });
+      this.activeInstanceId = id;
+      uiState.setStatus("Active instance changed");
+    } catch (e) {
+      console.error("Failed to set active instance:", e);
+      uiState.setStatus("Error setting active instance: " + e);
+    }
+  }
+
+  async duplicateInstance(id: string, newName: string): Promise<Instance | null> {
+    try {
+      const instance = await invoke<Instance>("duplicate_instance", {
+        instanceId: id,
+        newName,
+      });
+      await this.loadInstances();
+      uiState.setStatus(`Instance duplicated as "${newName}"`);
+      return instance;
+    } catch (e) {
+      console.error("Failed to duplicate instance:", e);
+      uiState.setStatus("Error duplicating instance: " + e);
+      return null;
+    }
+  }
+
+  async getInstance(id: string): Promise<Instance | null> {
+    try {
+      return await invoke<Instance>("get_instance", { instanceId: id });
+    } catch (e) {
+      console.error("Failed to get instance:", e);
+      return null;
+    }
+  }
+}
+
+export const instancesState = new InstancesState();