fix: handle object-format capabilities in normalizeCapabilities

When capabilities is configured as an object (e.g., { inlineButtons: "dm" })
instead of a string array, normalizeCapabilities() would crash with
"capabilities.map is not a function".

This can occur when using the new Telegram inline buttons scoping feature:
  channels.telegram.capabilities.inlineButtons = "dm"

The fix adds an Array.isArray() guard to return undefined for non-array
capabilities, allowing channel-specific handlers (like
resolveTelegramInlineButtonsScope) to process the object format separately.

Fixes crash when using object-format TelegramCapabilitiesConfig.

src/config/channel-capabilities.ts

@@ -4,6 +4,9 @@ import type { ClawdbotConfig } from "./config.js";
 
 function normalizeCapabilities(capabilities: string[] | undefined): string[] | undefined {
   if (!capabilities) return undefined;
+  // Handle object-format capabilities (e.g., { inlineButtons: "dm" }) gracefully.
+  // Channel-specific handlers (like resolveTelegramInlineButtonsScope) process these separately.
+  if (!Array.isArray(capabilities)) return undefined;
   const normalized = capabilities.map((entry) => entry.trim()).filter(Boolean);
   return normalized.length > 0 ? normalized : undefined;
 }