Bug Report: requires_password: false configuration fails validation

描述

When setting requires_password: false in network.yaml to allow passwordless connections, the network fails to start due to a validation error that requires all agent_groups to have a password_hash defined.

Expected Behavior

According to the documentation and design intent, when requires_password: false is set:

• Agents should be able to connect without providing a password
• They should be assigned to the default_agent_group
• The default_agent_group should not require a password_hash

Actual Behavior

Network fails to start with error:

Value error, Group 'public' must have 'password_hash' defined

Steps to Reproduce

1. Create a network.yaml with requires_password: false:

network:
  name: "test-network"
  requires_password: false
  default_agent_group: public
  agent_groups:
    public:
      description: "Public access - no password required"
      metadata:
        permissions: ["read", "write"]
    # other groups with passwords...

2. Run: openagents network start
3. Error: Validation fails

Root Cause

In src/openagents/models/network_config.py, the validate_agent_groups validator forces every group to have a password_hash, regardless of requires_password setting:

@field_validator("agent_groups")
def validate_agent_groups(cls, v):
    for group_name, group_config in v.items():
        if not group_config.password_hash:  # This check is too strict
            raise ValueError(f"Group '{group_name}' must have 'password_hash' defined")

Meanwhile, the design intent (shown in tests and topology code) supports passwordless mode when requires_password=False.

Workaround

Currently, passwordless mode only works when setting config.requires_password = False at runtime (after network initialization), not via YAML configuration.

Environment

• OpenAgents version: 0.8.5.post5
• Python: 3.13
• OS: Linux

Related Code

• Test: tests/network/test_agent_groups.py::test_requires_password_false_no_password
• Topology: src/openagents/core/topology.py (supports password_hash=None)
• Config: src/openagents/models/network_config.py (validation too strict)

Suggested Fix

Modify validate_agent_groups to allow password_hash=None for groups when the group doesn't require authentication, or remove the strict validation and let the topology layer handle password validation based on requires_password setting.