Resolve DIDs to handles in command output

Context

The tangled issue view command currently displays the author as a raw DID:

Issue #4 [OPEN]
Title: PR Phase 1: Create, List, and View Pull Requests
Author: did:plc:b2mcbcamkwyznc5fkplwlxbf
Created: today

A raw DID like did:plc:b2mcbcamkwyznc5fkplwlxbf is opaque — it carries no meaningful information for a human reader and wastes tokens in LLM workflows. The tangled auth status command already resolves the logged-in user's DID to a handle (@markbennett.ca), so the resolution capability exists in the codebase.

Tasks

• Create src/utils/at-handle.ts with a resolveHandle(did: string): Promise<string> function that returns the human-readable handle for a given DID, or falls back to the raw DID if resolution fails.
• Audit all commands that display an author, actor, or identity field and update them to use resolveHandle(). Known locations to update include:
  • tangled issue view — Author: field
  • Any other commands added in future that display a DID to the user
• Use the AT Protocol identity resolution (e.g. com.atproto.identity.resolveHandle or the reverse DID document lookup) to fetch the handle.
• Fall back gracefully to displaying the raw DID if resolution fails or is unavailable.
• Cache resolved handles within a single command invocation to avoid redundant network calls when the same DID appears multiple times.
• Add tests for resolveHandle() covering success, failure/fallback, and cache behaviour.

Notes

The resolution should live in src/utils/at-handle.ts so it is reusable across all commands, following the project pattern of keeping utilities in src/utils/. This utility will become increasingly useful as more commands (PR view, repo view, etc.) are added that display actor information.