feat(solo): beginner-friendly onboarding — smart setup guide + direct config commands

start.sh:
- Interactive Telegram Bot Token prompt on first run
- Token format validation (must match 12345:ABC... pattern)
- Friendly step-by-step startup instructions after launch

telegram/bot.go:
- /start now shows context-aware setup guide based on actual config state:
  - No AI model → explains how to configure, lists all providers
  - AI model OK but no exchange → guides to configure exchange via chat
  - All configured → full capabilities welcome message
- New: direct setup commands ('配置 deepseek sk-xxx') bypass LLM entirely
  so AI model can be configured even before any model exists (bootstrap fix)
- All messages now in Chinese (匹配用户语言)

telegram/agent/prompt.go:
- Added first-time setup detection section
- Agent told to never ask user to visit web UI — everything via chat

telegram/agent/prompt.go

@@ -30,6 +30,12 @@ Use the api_request tool to call the NOFX REST API:
 4. When user provides enough info, act immediately — no confirmation needed
 5. Be decisive — infer intent from context, use schema to fill in smart defaults
 
+## First-time Setup Detection
+Check Account State at conversation start:
+- If AI Models shows all disabled/unconfigured AND Exchanges empty → tell user to send /start for setup guide
+- If Exchanges empty but models OK → guide user to configure exchange: ask for exchange type + API credentials in ONE message
+- Never ask user to visit the web UI — everything can be done via chat
+
 ## Verification Rule (CRITICAL)
 After ANY PUT or POST that creates or modifies a resource:
 1. Immediately GET the resource to read actual saved values