fix(docker): include package directory in image

[JTJag]

Summary

Fix Docker runtime startup failures after upstream project restructuring.

Why

After recent upstream changes, container startup failed with:

• ModuleNotFoundError: No module named 'telegram_mcp'
  because the package directory was not copied into the image.

With package copy fixed, startup then failed on env parsing due to empty API ID default:

• ValueError: invalid literal for int() with base 10: ''

Validation

• docker build -t telegram-mcp:smoke . passes.
• Runtime no longer fails on missing package import.
• Runtime now correctly proceeds to Telethon credential validation (requires real TELEGRAM_API_ID/TELEGRAM_API_HASH at run time).