v1.0.7

feat(autobuy): add configurable quota threshold for auto-buy

Introduce `AutoBuyThreshold` to session data. Implement UI in Telegram
bot and CLI to set and display the threshold. Update auto-buy monitor
logic to trigger purchase when internet quota falls below the threshold.
Add `ParseQuotaToMB` utility for quota string conversion. Extend MCP
`start_auto_buy` tool with `threshold_mb` parameter.

This allows users to proactively manage internet quota, ensuring a new
package is purchased before complete depletion, improving connectivity.