feat: workspace frontend integration (PR-4)

- Add workspace_id parameter to createInstance API client
- Wire WorkspacesPage 'Start Tool' modal to createInstance + startInstance
- Pass workspace_id when creating instance from workspace page
- TypeScript + eslint clean

apps/web/src/pages/workspaces.tsx

@@ -7,6 +7,7 @@ import { useWorkspaceActions } from "../hooks/use-workspace-actions";
 import { WorkspaceCard } from "../components/workspace-card";
 import { WorkspaceCreateForm } from "../components/workspace-create-form";
 import { StartToolModal } from "../components/start-tool-modal";
+import { createInstance, startInstance } from "../api/sessions";
 import type { Workspace } from "../types/workspace";
 
 export function WorkspacesPage() {
@@ -36,9 +37,25 @@ export function WorkspacesPage() {
 
   const handleStartTool = async (toolTypeId: string, configProfileId?: string) => {
     if (!startWorkspace) return;
-    // TODO: Call instance creation API with workspace_id
-    console.log("Start tool", { toolTypeId, configProfileId, workspace: startWorkspace.id });
-    setStartWorkspace(null);
+    try {
+      const instance = await createInstance(
+        projectId,
+        repoId,
+        toolTypeId,
+        `${startWorkspace.name} - ${toolTypeId}`,
+        undefined,
+        undefined,
+        undefined,
+        configProfileId,
+        [],
+        startWorkspace.id
+      );
+      await startInstance(projectId, repoId, instance.id, configProfileId);
+      setStartWorkspace(null);
+      await refresh();
+    } catch (err) {
+      alert(err instanceof Error ? err.message : "Failed to start tool");
+    }
   };
 
   return (