Add RADIUS authentication modules

[Copilot]

Implements Ansible modules for HashiCorp Vault RADIUS authentication using the hvac library's Radius API.

Modules

• hashivault_radius_config: Configure RADIUS backend (host, secret, port, dial_timeout, nas_port, unregistered_user_policies)
• hashivault_radius_user: Manage RADIUS users and policy assignments (create/update/delete)

Both modules implement idempotency via configuration comparison and support check mode.

Integration

• Added RADIUS to hashivault_auth() for credential-based authentication
• Updated VAULT_AUTHTYPE documentation to include radius

Example Usage

# Configure RADIUS backend
- hashivault_radius_config:
    host: radius.example.com
    secret: "{{ radius_shared_secret }}"
    port: 1812

# Manage user policies
- hashivault_radius_user:
    name: alice
    policies:
      - default
      - app-read
    state: present

Authenticate via environment:

export VAULT_AUTHTYPE=radius
export VAULT_USER=alice
export VAULT_PASSWORD=secret

Test Coverage

• test_radius_config.yml: Configuration idempotency and policy assignments
• test_radius_user.yml: User CRUD operations and policy updates

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Add RADIUS modules</issue_title>
<issue_description>Create ansible modules to support RADIUS using https://python-hvac.org/en/stable/source/hvac_api_auth_methods.html#hvac.api.auth_methods.Radius</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Add RADIUS modules #500

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[TerryHowe]

@copilot fix broken tests

[itsphoebe]

@copilot fix bug to write a config when the current state is empty. In hashivault_radius_config if Radius auth is newly enabled, it wont write the config to Vault.

[itsphoebe]

Sorry if I'm doing this incorrectly!
I was testing out this PR and it wasnt properly adding the config after radius auth was enabled so added that change into this PR 503
Tested locally and it was able to config to my lab radius server!

[drewmullen]

@itsphoebe was able to show me that these changes worked for adding the mount and a user role

[TerryHowe]

Is that an approval/lgtm?

[drewmullen]

LGTM but legit this time ✌️

yes and tyvm! nice working with ya again!

[TerryHowe]

Available with 5.6.0