Add System Package Installation Support

[spboyer]

Description

Support installing system packages (apt, apk, etc.) needed by Python packages.

Current State

Only Python packages can be installed.

Proposed Implementation

• Detect system package requirements from deps
• Support apt (Debian/Ubuntu) and apk (Alpine)
• Allow explicit system package declaration
• Auto-detect common deps (libpq for psycopg2, etc.)

Use Cases

• Installing database client libraries
• Native dependencies for packages
• System tools needed by app

Example

system_packages:
  - libpq-dev
  - gcc
  - build-essential

Priority

Medium-High - Common need for production apps.

Parent: #48