fix: prioritize OPENCODE_CONFIG_DIR for AGENTS.md

[lgladysz]

Summary

When OPENCODE_CONFIG_DIR is set, the AGENTS.md from that directory should be loaded instead of the global one. Currently, global ~/.config/opencode/AGENTS.md is always checked first and the loop breaks, so profile-specific AGENTS.md is never reached.

Changes

• Check OPENCODE_CONFIG_DIR first in globalFiles() and return early if set
• This makes profiles isolated environments with their own configuration

Test Plan

1. Create global AGENTS.md: echo "# Global" > ~/.config/opencode/AGENTS.md
2. Create profile AGENTS.md: mkdir -p ~/.config/opencode/profiles/work && echo "# Work" > ~/.config/opencode/profiles/work/AGENTS.md
3. Set OPENCODE_CONFIG_DIR=~/.config/opencode/profiles/work
4. Verify only the profile AGENTS.md is loaded

How I verified it is working:

1. I prepared the AGENTS.md structure (global and profile).
2. Ran OPENCODE_CONFIG_DIR=~/.config/opencode/profiles/work bun dev.
3. Written hi in opencode.
4. Result as below:

Fixes #11534

[github-actions]

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

Based on my search, I found one potentially related PR:

Related PR found:

• PR feat(config): add OPENCODE_DISABLE_GLOBAL_CONFIG env var #10013: "feat(config): add OPENCODE_DISABLE_GLOBAL_CONFIG env var"
  • feat(config): add OPENCODE_DISABLE_GLOBAL_CONFIG env var #10013
  • This PR addresses similar concerns about global configuration precedence and may relate to the configuration loading order issue being fixed in PR fix: prioritize OPENCODE_CONFIG_DIR for AGENTS.md #11536.

The other results (PR #952 and #9657) appear to be about AGENTS.md recursive loading and subdirectory rule loading, which are different features rather than duplicates of the prioritization fix.