feat(examples): add Telegram customer support demo

[xe-nvdk]

Summary

• 3 Telegram bots (Internet/TV/Billing) for a fictional telco "TeleCo", sharing Memtrace memory across departments
• Cross-department memory sharing: recall/search by session_id, write with agent_id for attribution
• Session resume on restart via account_id metadata lookup
• Photo support via multimodal Claude messages (base64-encoded images)
• Identity verification flow with test customer database
• All secrets via environment variables — no hardcoded tokens

Test plan

• Verify no secrets/tokens in telegram_support.py
• pip install -r examples/claude/requirements.txt installs all deps
• Set 6 env vars, run python examples/claude/telegram_support.py — all 3 bots start
• Message Bot 1 with customer name → verified, ask about internet issue → stored in Memtrace
• Message Bot 2 with same name → instant verify, sees Bot 1 history
• Message Bot 3 → sees all departments' history, offers proactive credit