feat(config): gate channel config writes

src/config/zod-schema.providers-whatsapp.ts

@@ -11,6 +11,7 @@ export const WhatsAppAccountSchema = z
   .object({
     name: z.string().optional(),
     capabilities: z.array(z.string()).optional(),
+    configWrites: z.boolean().optional(),
     enabled: z.boolean().optional(),
     messagePrefix: z.string().optional(),
     /** Override auth directory for this WhatsApp account (Baileys multi-file auth state). */
@@ -60,6 +61,7 @@ export const WhatsAppConfigSchema = z
   .object({
     accounts: z.record(z.string(), WhatsAppAccountSchema.optional()).optional(),
     capabilities: z.array(z.string()).optional(),
+    configWrites: z.boolean().optional(),
     dmPolicy: DmPolicySchema.optional().default("pairing"),
     messagePrefix: z.string().optional(),
     selfChatMode: z.boolean().optional(),