Move CLI-only recipient parsing out of EmailPopulatingBuilder

[bbottema]

Context

The recipient API cleanup in #613 deliberately reduced the public EmailPopulatingBuilder surface, but retained withRecipients(String name, boolean fixedName, RecipientType type, String... addresses) for CLI and property-backed configuration.

While resolving #682, the dedicated --email:to, --email:cc, and --email:bcc commands were restored through an internal CLI facade. The remaining string-parsing bridge belongs on that same facade rather than on the supported Java builder API.

Change

• Move the generic string-based recipient parser to the internal CLI support interface.
• Keep withRecipients(Recipient...) and withRecipients(Collection<Recipient>) public.
• Preserve CLI and property-backed recipient parsing.
• Regenerate packaged CLI metadata and guard the public/internal API boundary with tests.

This removes a previously public method, so it is intentionally scheduled for the next minor release rather than the 9.1.7 patch tracked by #682.

Related: #613, #682.

[bbottema]

Implemented in ece38c34:

• moved the generic string-based recipient parser to the internal CLI support facade;
• retained the object-based Recipient... and Collection<Recipient> overloads on EmailPopulatingBuilder;
• preserved CLI and property-backed recipient parsing and regenerated the packaged CLI metadata.

This change is isolated from #682 so v9.1.7 can remain a patch-only release. Closing as completed for v9.2.0.

[bbottema]

This issue's change is now available in Simple Java Mail 9.2.0 and from Maven Central.