[FEATURE]: Docs: clarify that local and global AGENTS.md are both loaded, not exclusive #33908

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

I wanted to know if opencode loads both a project AGENTS.md and my global ~/.config/opencode/AGENTS.md at the same time.

The docs currently say:

When opencode starts, it looks for rule files in this order:

1. Local files by traversing up from the current directory (AGENTS.md, CLAUDE.md)
2. Global file at ~/.config/opencode/AGENTS.md
3. Claude Code file at ~/.claude/CLAUDE.md (unless disabled)

The first matching file wins in each category.

That reads like only one file wins overall.

But earlier the same page says:

"opencode also supports reading the AGENTS.md file from multiple locations."

I'm not sure if local and global are combined, or if having a local file disables the global one.

Request
Please rephrase the Precedence section to make it explicit that:

• all three layers are loaded and concatenated in order
• "first wins" only applies within each layer (AGENTS.md beats CLAUDE.md)