feat(auth): multi-account support with auto-rotation

[IsraelAraujo70]

Summary

Add multi-account support to OpenCode authentication system, inspired by the Antigravity plugin.

Changes

• New auth storage format: { provider: { accounts: {}, activeAccount } }
• Auto-migration: seamless upgrade from legacy single-account format
• Interactive CLI: no more --account flags, just run opencode auth login
• Account management: switch, enable/disable accounts interactively
• Environment variables: OPENCODE_ACCOUNT_OPENAI=work for account selection
• Auto-rotation: getNextAccount() for rate-limit handling (WIP)

Example Usage

# Add first account
opencode auth login openai

# Add second account (will prompt interactively)
opencode auth login openai

# Switch account
opencode auth use

# Or use env var
OPENCODE_ACCOUNT_OPENAI=personal opencode run ...

Related

• Inspired by: https://github.com/NoeFabris/opencode-antigravity-auth

[github-actions]

Thanks for your contribution!

This PR doesn't have a linked issue. All PRs must reference an existing issue.

Please:

1. Open an issue describing the bug/feature (if one doesn't exist)
2. Add Fixes #<number> or Closes #<number> to this PR description

See CONTRIBUTING.md for details.

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Based on my search, I found several potentially related PRs:

Potential Duplicates/Related PRs:

1. PR feat: multi-account profile support per provider #13218 - feat: multi-account profile support per provider

   • Very similar feature focusing on multi-account profile support per provider

2. PR feat(auth): multi-account OAuth support with auto-relogin #11832 - feat(auth): multi-account OAuth support with auto-relogin

   • Addresses multi-account OAuth support with auto-relogin functionality

3. PR feat(auth): OAuth Marathon - multi-account credential rotation #8590 - feat(auth): OAuth Marathon - multi-account credential rotation

   • Previous attempt at multi-account credential rotation/auto-rotation feature

4. PR feat(auth): merge auth methods from multiple plugins for same provider #10528 - feat(auth): merge auth methods from multiple plugins for same provider

   • Related to handling multiple authentication methods for the same provider

5. PR feat(openai-oauth) OpenAI OAuth multi account support #8536 - feat(openai-oauth) OpenAI OAuth multi account support

   • Earlier work on OpenAI OAuth multi-account support

Note: PR #13218 and #11832 appear to be the most directly related to PR #13378, as they both address multi-account support with similar goals. You may want to check if these are addressing the same requirements or if they can be consolidated.