feat: add configurable Call-ID generators

[darwvin-dev]

Summary:
Add a new -cid_type option for built-in Call-ID generators while keeping -cid_str as the default behavior. This adds UUID, compact UUID, random, and timestamp-based Call-ID modes, along with unit coverage for each mode.

Reasoning:
-cid_str is flexible and should remain the default, but it still assumes callers want to describe the Call-ID shape as a formatting pattern. In practice there are cases where a ready-made generator is more convenient or more consistent: interoperability testing against systems that expect UUID-like identifiers, quickly switching between predictable and opaque identifiers during troubleshooting, and avoiding repeated hand-built templates for common styles.

This change keeps backward compatibility by leaving -cid_str and the legacy formatting path untouched unless -cid_type is explicitly selected. The new modes provide a small set of built-in generators that cover the common cases without removing the existing customization path.

What is included:

• New -cid_type CLI option.
• Built-in default, uuid, uuid-compact, random, and timestamp generator modes.
• Existing -cid_str behavior retained as the default path.
• Unit coverage for each mode.

What is not included:

• No startup wizard behavior. That is split into a separate PR for review on its own merits.