gh should auto-select account based on repo remote / git config #13529

Problem

gh supports multiple authenticated accounts but requires manual gh auth switch every time you move between repos owned by different accounts. This is a constant source of friction — 404s, PRs attributed to the wrong account, CI triggered under the wrong identity.

Anyone managing separate personal and work GitHub accounts (which is extremely common) hits this daily.

Expected Behavior

gh should automatically select the correct authenticated account based on the current repo context. Two natural resolution strategies:

1. git config github.account — works with git's existing includeIf / conditional includes, zero new config surface
2. Remote origin org matching — map orgs to accounts in gh config, zero per-repo setup

Either way: cd into a repo, run gh pr create, correct account is used. No manual switching.

Current Workaround

A shell wrapper that calls gh auth switch before every invocation. It works but:

• Mutates global state (not safe for concurrent terminal sessions)
• Adds latency to every gh command
• Shouldn't be necessary for something this fundamental

Prior Art

• Feature: Auto-switch accounts based on git config #12459 — identical feature request, open since Feb 2026, strong community support
• feat: auto-switch accounts based on git config github.account #12628 — clean 22-line implementation PR that was closed because the issue wasn't labeled help wanted, not because of any technical concern
• Allow configuring ssh host and optionally do account detection based on it #9740 — SSH host-based account detection (related)
• Git itself solved this years ago with includeIf

The implementation is trivial — a single check in ActiveUser() before falling back to the stored active user. A working PR already exists. This should be a priority for the multi-account experience.