Add org switcher with create, switch, and delete

The sidebar org button was inert: clicking it did nothing. Add a real
dropdown menu listing every organization, a "New organization" entry
that re-enters onboarding without resetting the database, and a per-org
delete affordance with inline confirmation. Active org is now persisted
in a single-row app_state table so the snapshot keeps a stable
selection across restarts and the renderer drives switching via two new
IPC channels (setActiveOrganization, deleteOrganization).

- migration 006 adds app_state(id=1, active_org_id, updated_at)
- snapshot resolves active org from app_state with the first-org fallback
- OrganizationService gains setActive + delete + bootstrap upsert
- new OrgSwitcher renderer component keeps Shell.tsx lean

AgentCompany-New/src/shared/commands.ts

@@ -6,6 +6,14 @@ import type {
   TaskStatus,
 } from "./domain";
 
+export interface SetActiveOrganizationInput {
+  orgId: string;
+}
+
+export interface DeleteOrganizationInput {
+  orgId: string;
+}
+
 export interface CreateOrganizationInput {
   organizationName: string;
   description?: string;

AgentCompany-New/src/shared/desktop-api.ts

@@ -15,12 +15,14 @@ import type {
   CreateSocialAccountInput,
   CreateTaskInput,
   DecideApprovalInput,
+  DeleteOrganizationInput,
   ImportFileInput,
   ImportSkillDirectoryInput,
   LaunchSocialLoginInput,
   ResolveAgentSkillsInput,
   SaveProviderCredentialInput,
   SendMessageInput,
+  SetActiveOrganizationInput,
   SetFilePinnedInput,
   SetScheduledPostStateInput,
   UpdateTaskStatusInput,
@@ -33,6 +35,8 @@ export interface RendererEvent {
 export interface DesktopApi {
   loadSnapshot(): Promise<DesktopResult<AppSnapshot>>;
   bootstrapOnboarding(input: BootstrapOnboardingInput): Promise<DesktopResult<BootstrapOnboardingSummary>>;
+  setActiveOrganization(input: SetActiveOrganizationInput): Promise<DesktopResult<AppSnapshot>>;
+  deleteOrganization(input: DeleteOrganizationInput): Promise<DesktopResult<AppSnapshot>>;
   createOrganization(input: CreateOrganizationInput): Promise<DesktopResult<AppSnapshot>>;
   createAgent(input: CreateAgentInput): Promise<DesktopResult<AppSnapshot>>;
   createTask(input: CreateTaskInput): Promise<DesktopResult<AppSnapshot>>;

AgentCompany-New/src/shared/ipc.ts

@@ -1,6 +1,8 @@
 export const IPC_CHANNELS = {
   loadSnapshot: "agentcompany:load-snapshot",
   bootstrapOnboarding: "agentcompany:bootstrap-onboarding",
+  setActiveOrganization: "agentcompany:set-active-organization",
+  deleteOrganization: "agentcompany:delete-organization",
   createOrganization: "agentcompany:create-organization",
   createAgent: "agentcompany:create-agent",
   createTask: "agentcompany:create-task",