fix(tauri): update @reserved annotations + remove dead SaaS client methods

- Update 9 @reserved → @connected for commands with frontend consumers:
  zclaw_status, zclaw_start, zclaw_stop, zclaw_restart, zclaw_doctor,
  viking_add_with_metadata, viking_store_with_summaries,
  trigger_execute, scheduled_task_create
- Remove 10 dead SaaS client methods with zero callers:
  healthCheck, listDevices (saas-client.ts)
  getRelayTask, getUsage/relay (saas-relay.ts)
  listPrompts, getPrompt, listPromptVersions, getPromptVersion (saas-prompt.ts)
  getPlan, getUsage/billing (saas-billing.ts)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

desktop/src/lib/saas-relay.ts

@@ -7,7 +7,6 @@
 
 import type {
   RelayTaskInfo,
-  UsageStats,
 } from './saas-types';
 import { createLogger } from './logger';
 const logger = createLogger('SaaSRelay');
@@ -27,11 +26,6 @@ export function installRelayMethods(ClientClass: { prototype: any }): void {
     return this.request<RelayTaskInfo[]>('GET', `/api/v1/relay/tasks${qs ? '?' + qs : ''}`);
   };
 
-  /** Get a single relay task */
-  proto.getRelayTask = async function (this: { request<T>(method: string, path: string, body?: unknown): Promise<T> }, taskId: string): Promise<RelayTaskInfo> {
-    return this.request<RelayTaskInfo>('GET', `/api/v1/relay/tasks/${taskId}`);
-  };
-
   /** Retry a failed relay task (admin only) */
   proto.retryRelayTask = async function (this: { request<T>(method: string, path: string, body?: unknown): Promise<T> }, taskId: string): Promise<{ ok: boolean; task_id: string }> {
     return this.request<{ ok: boolean; task_id: string }>('POST', `/api/v1/relay/tasks/${taskId}/retry`);
@@ -117,16 +111,4 @@ export function installRelayMethods(ClientClass: { prototype: any }): void {
     throw new Error('chatCompletion: all attempts exhausted');
   };
 
-  // --- Usage Statistics ---
-
-  /** Get usage statistics for current account */
-  proto.getUsage = async function (this: { request<T>(method: string, path: string, body?: unknown): Promise<T> }, params?: { from?: string; to?: string; provider_id?: string; model_id?: string }): Promise<UsageStats> {
-    const qs = new URLSearchParams();
-    if (params?.from) qs.set('from', params.from);
-    if (params?.to) qs.set('to', params.to);
-    if (params?.provider_id) qs.set('provider_id', params.provider_id);
-    if (params?.model_id) qs.set('model_id', params.model_id);
-    const query = qs.toString();
-    return this.request<UsageStats>('GET', `/api/v1/usage${query ? '?' + query : ''}`);
-  };
 }