Add entry point support to load_environment

[AmeenP]

Summary

This PR adds Python entry point support to load_environment(), enabling namespace-aware environment loading with owner/name format.

Changes

Core Functionality

• New priority-based loading system:

  1. Explicit target spec (module:attr) - highest priority
  2. Entry point exact match - preferred for owner/name format
  3. Module import fallback - backward compatibility

• New helper functions:

  • _call_loader(): Common loader with parameter inspection and logging
  • _load_from_target_spec(): Handles explicit module:attr targets
  • _load_via_entry_point_exact(): Entry point discovery and loading via importlib.metadata

Improvements

• Cleaner, more modular code structure
• Better error messages with contextual information
• Support for namespaced environment IDs (owner/name)
• Backward compatible with existing environments

Testing

All tests passed:

• ✓ Entry point discovery and registration
• ✓ Load via entry point (exact match ameenp/wordle)
• ✓ Load via fallback (module name wordle)
• ✓ Load via explicit target spec (wordle:load_environment)
• ✓ Priority order working correctly

Example Usage

from verifiers import load_environment

# Via entry point (preferred for owner/name)
env = load_environment("ameenp/wordle")

# Via explicit target
env = load_environment("wordle:load_environment")

# Via fallback (backward compatible)
env = load_environment("wordle")

Related

• Companion PR for prime-cli: Add entry point management to prime env push prime#126