refactor(desktop): split kernel_commands/pipeline_commands into modules, add SaaS client libs and gateway modules

Split monolithic kernel_commands.rs (2185 lines) and pipeline_commands.rs (1391 lines)
into focused sub-modules under kernel_commands/ and pipeline_commands/ directories.
Add gateway module (commands, config, io, runtime), health_check, and 15 new
TypeScript client libraries for SaaS relay, auth, admin, telemetry, and kernel
sub-systems (a2a, agent, chat, hands, skills, triggers).

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

desktop/src/lib/gateway-client.ts

@@ -74,6 +74,7 @@ import {
 import type { GatewayConfigSnapshot, GatewayModelChoice } from './gateway-config';
 import { installApiMethods } from './gateway-api';
 import { createLogger } from './logger';
+import { GatewayHttpError } from './gateway-errors';
 
 const log = createLogger('GatewayClient');
 
@@ -712,10 +713,8 @@ export class GatewayClient {
     const baseUrl = this.getRestBaseUrl();
     const response = await fetch(`${baseUrl}${path}`);
     if (!response.ok) {
-      // For 404 errors, throw with status code so callers can handle gracefully
-      const error = new Error(`REST API error: ${response.status} ${response.statusText}`);
-      (error as any).status = response.status;
-      throw error;
+      const errorBody = await response.text().catch(() => '');
+      throw new GatewayHttpError(`HTTP ${response.status}: ${errorBody || response.statusText}`, response.status, errorBody);
     }
     return response.json();
   }
@@ -734,10 +733,7 @@ export class GatewayClient {
     if (!response.ok) {
       const errorBody = await response.text().catch(() => '');
       log.error(`POST ${url} failed: ${response.status} ${response.statusText}`, errorBody);
-      const error = new Error(`REST API error: ${response.status} ${response.statusText}`);
-      (error as any).status = response.status;
-      (error as any).body = errorBody;
-      throw error;
+      throw new GatewayHttpError(`HTTP ${response.status}: ${errorBody || response.statusText}`, response.status, errorBody);
     }
 
     const result = await response.json();
@@ -932,8 +928,8 @@ export class GatewayClient {
           } else {
             originalHandler?.call(this.ws!, evt);
           }
-        } catch {
-          // Ignore parse errors
+        } catch (e) {
+          log.debug('Parse error in handshake response handler', { error: e });
         }
       };
 
@@ -969,14 +965,14 @@ export class GatewayClient {
     const listeners = this.eventListeners.get(event);
     if (listeners) {
       for (const cb of listeners) {
-        try { cb(payload); } catch { /* ignore listener errors */ }
+        try { cb(payload); } catch (e) { log.debug('Event listener error', { error: e }); }
       }
     }
     // Also emit wildcard
     const wildcardListeners = this.eventListeners.get('*');
     if (wildcardListeners) {
       for (const cb of wildcardListeners) {
-        try { cb({ event, payload }); } catch { /* ignore */ }
+        try { cb({ event, payload }); } catch (e) { log.debug('Wildcard event listener error', { error: e }); }
       }
     }
   }
@@ -1003,7 +999,7 @@ export class GatewayClient {
       this.ws.onclose = null;
       this.ws.onerror = null;
       if (this.ws.readyState === WebSocket.OPEN || this.ws.readyState === WebSocket.CONNECTING) {
-        try { this.ws.close(); } catch { /* ignore */ }
+        try { this.ws.close(); } catch (e) { log.debug('WebSocket close failed during cleanup', { error: e }); }
       }
       this.ws = null;
     }
@@ -1117,9 +1113,9 @@ export class GatewayClient {
     this.reconnectTimer = window.setTimeout(async () => {
       try {
         await this.connect();
-      } catch {
+      } catch (e) {
         /* close handler will trigger another reconnect */
-        this.log('warn', `Reconnect attempt ${this.reconnectAttempts} failed`);
+        this.log('warn', `Reconnect attempt ${this.reconnectAttempts} failed: ${e instanceof Error ? e.message : String(e)}`);
       }
     }, delay);
   }