feat: add instance list component and integrate into workspace

- Create InstanceList component with create/start/stop/restart/delete
- Add tool instance icons (external, play, stop)
- Integrate InstanceList into RepoWorkspace sidebar
- Load tool types for instance creation
- Add instance-specific CSS styles

Quality gates: typecheck ✓, lint ✓, build ✓

apps/web/src/pages/repo-workspace.tsx

@@ -13,7 +13,10 @@ import {
 import { CommitPanel } from "../components/commit-panel";
 import { FileEditor } from "../components/file-editor";
 import { GitToolbar } from "../components/git-toolbar";
+import { InstanceList } from "../components/instance-list";
 import { WorkspaceHeader } from "../components/workspace-header";
+import { listToolTypes } from "../api/tool_types";
+import type { ToolType } from "../api/tool_types";
 
 type WorkspaceStatus = "loading" | "ready" | "error" | "empty";
 
@@ -50,6 +53,7 @@ export const RepoWorkspace = () => {
   const [branches, setBranches] = useState<string[]>([]);
   const [currentBranch, setCurrentBranch] = useState<string>("main");
   const [gitStatus, setGitStatus] = useState<GitStatus | null>(null);
+  const [toolTypes, setToolTypes] = useState<ToolType[]>([]);
 
   const loadProject = useCallback(async () => {
     if (!projectId) return;
@@ -114,10 +118,20 @@ export const RepoWorkspace = () => {
     }
   }, [projectId, selectedRepoId]);
 
+  const loadToolTypes = useCallback(async () => {
+    try {
+      const data = await listToolTypes();
+      setToolTypes(data);
+    } catch {
+      setToolTypes([]);
+    }
+  }, []);
+
   useEffect(() => {
     void loadProject();
     void loadRepositories();
-  }, [loadProject, loadRepositories]);
+    void loadToolTypes();
+  }, [loadProject, loadRepositories, loadToolTypes]);
 
   useEffect(() => {
     void loadBranches();
@@ -234,6 +248,13 @@ export const RepoWorkspace = () => {
                     }}
                   />
                 )}
+                {selectedRepoId && (
+                  <InstanceList
+                    projectId={projectId!}
+                    repoId={selectedRepoId}
+                    toolTypes={toolTypes}
+                  />
+                )}
               </>
             )}
           </aside>