@spec resolve_handle(String.t() | nil, String.t()) ::
  {:ok, String.t()} | {:error, term()}

Resolves a handle to a DID via the com.atproto.identity.resolveHandle XRPC endpoint.

This is the plain wire endpoint: the resolution is performed server-side by the given PDS and no session is required. The DNS/HTTPS resolver of resolve_handle/1 stays the default; prefer it unless you specifically want the PDS's view of the handle.

Pass nil as pds_url to use the default base URL, or the PDS base URL (bare or /xrpc-suffixed, normalized internally).

https://docs.bsky.app/docs/api/com-atproto-identity-resolve-handle

Performs complete syntactic validation of a DID according to AT Protocol specifications.

A valid DID must:

• Start with "did:"
• Have a supported method (plc or web)
• Contain a valid method-specific identifier
• Use only allowed characters (a-z, A-Z, 0-9, ., _, :, %, -)

Performs complete syntactic validation of a handle.

Validates according to AT Protocol handle specification:

• Must be at least two segments separated by dots
• Each segment must be 1-63 chars
• Segments must start/end with alphanumeric
• Segments can contain hyphens (not at start/end)
• Last segment cannot start with a number