Make bux onboarding voice shorter

[mathisdittrich]

summary

• make the system prompt push for lowercase, concise, lightly sassy replies
• shorten first Telegram onboarding/help messages
• allow two tiny back-to-back messages instead of one chunky one

tests

• /opt/bux/venv/bin/python -m py_compile agent/telegram_bot.py
• /opt/bux/venv/bin/python -m unittest agent.test_telegram_bot

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Summary by cubic

Shortened Telegram onboarding/help and tightened the system voice to be lowercase, concise, and lightly sassy. Adds support for sending two short back-to-back messages on /start.

• Refactors
  • Telegram: /start now sends two brief messages; /help is shorter; command descriptions and prompts use lowercase; onboarding bind/activate messages are tighter.
  • System prompt: clarified tone (casual, dry humor, lowercase by default), favors one-line replies, allows two tiny back-to-back messages, and trims onboarding/topic prompts and card guidance.

^{Written for commit 09103ab. Summary will update on new commits. Review in cubic}

[cubic-dev-ai]

No issues found across 2 files

_{Re-trigger cubic}