Add HTTP Basic Authentication support for mock repository server

[Copilot]

Implements optional HTTP Basic Authentication for the Mock Repository Manager to support testing Maven configurations requiring authenticated repository access.

Changes

Configuration

• Added username and password parameters to AbstractStartMojo
• Configurable via plugin config or properties: -Dmrm.username=user -Dmrm.password=pass
• Authentication only enabled when username is provided (backward compatible)

Implementation

• Added jetty-security dependency
• Implemented HTTP Basic Auth using Jetty's ConstraintSecurityHandler and HashLoginService
• Protected all paths (/*) when credentials configured
• Added overloaded constructor to FileSystemServer accepting auth parameters

Testing

• Added FileSystemServerAuthTest covering:
  • 401 without credentials
  • 401 with invalid credentials
  • Success with valid credentials
  • No auth when username not configured

Usage

<plugin>
  <groupId>org.codehaus.mojo</groupId>
  <artifactId>mrm-maven-plugin</artifactId>
  <configuration>
    <username>testuser</username>
    <password>testpass</password>
  </configuration>
</plugin>

Client configuration in settings.xml:

<server>
  <id>mrm-repository</id>
  <username>testuser</username>
  <password>testpass</password>
</server>

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Support authentication on repository</issue_title>
<issue_description>Will probably require something like https://www.eclipse.org/jetty/documentation/current/configuring-security.html#_authentication_and_authorization_with_embedded_jetty</issue_description>

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

• Fixes Support authentication on repository #23

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.