feat: add ReportsToPicker for agent management

- Introduced ReportsToPicker component in AgentConfigForm and NewAgent pages to allow selection of an agent's manager.
- Updated organizational structure documentation to reflect the ability to change an agent's manager post-creation.
- Enhanced error handling in ConfigurationTab to provide user feedback on save failures.

ui/src/components/AgentConfigForm.tsx

@@ -44,6 +44,7 @@ import { ClaudeLocalAdvancedFields } from "../adapters/claude-local/config-field
 import { MarkdownEditor } from "./MarkdownEditor";
 import { ChoosePathButton } from "./PathInstructionsModal";
 import { OpenCodeLogoIcon } from "./OpenCodeLogoIcon";
+import { ReportsToPicker } from "./ReportsToPicker";
 
 /* ---- Create mode values ---- */
 
@@ -301,6 +302,12 @@ export function AgentConfigForm(props: AgentConfigFormProps) {
   });
   const models = fetchedModels ?? externalModels ?? [];
 
+  const { data: companyAgents = [] } = useQuery({
+    queryKey: selectedCompanyId ? queryKeys.agents.list(selectedCompanyId) : ["agents", "none", "list"],
+    queryFn: () => agentsApi.list(selectedCompanyId!),
+    enabled: Boolean(!isCreate && selectedCompanyId),
+  });
+
   /** Props passed to adapter-specific config field components */
   const adapterFieldProps = {
     mode,
@@ -447,6 +454,15 @@ export function AgentConfigForm(props: AgentConfigFormProps) {
                 placeholder="e.g. VP of Engineering"
               />
             </Field>
+            <Field label="Reports to" hint={help.reportsTo}>
+              <ReportsToPicker
+                agents={companyAgents}
+                value={eff("identity", "reportsTo", props.agent.reportsTo ?? null)}
+                onChange={(id) => mark("identity", "reportsTo", id)}
+                excludeAgentIds={[props.agent.id]}
+                chooseLabel="Choose manager…"
+              />
+            </Field>
             <Field label="Capabilities" hint={help.capabilities}>
               <MarkdownEditor
                 value={eff("identity", "capabilities", props.agent.capabilities ?? "")}