Fix plugin agent registration issue

[kill74]

Issue for this PR

Closes#25441

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

External plugins were being loaded, but agents provided by those plugins were not available in the agent selector.

This PR fixes the plugin agent registration path so agents from plugin modules are registered before the agent list is resolved. With this change, installing a plugin such as oh-my-opencode@3.17.12 correctly makes its agents available in the TUI.

I verified this by loading the plugin locally and confirming that its agents appeared in the agent selector.

How did you verify your code works?

Tested locally on Windows from the opencode repository.

I configured the plugin in .opencode/opencode.jsonc:

{
"plugin": ["oh-my-opencode@3.17.12"]
}

Then I started opencode and confirmed the plugin was loaded:

service=plugin path=oh-my-opencode@3.17.12 loading plugin

I also verified that:

• opencode starts normally after plugin initialization
• the /agent request completes successfully
• plugin-provided agents appear in the agent selector
• bun run --cwd packages/opencode typecheck passes

Screenshots / recordings

Plugin-provided agents now appear in the agent selector.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

Hey! Your PR title Fix plugin agent registration issue doesn't follow conventional commit format.

Please update it to start with one of:

• feat: or feat(scope): new feature
• fix: or fix(scope): bug fix
• docs: or docs(scope): documentation changes
• chore: or chore(scope): maintenance tasks
• refactor: or refactor(scope): code refactoring
• test: or test(scope): adding or updating tests

Where scope is the package name (e.g., app, desktop, opencode).

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 one potentially related PR:

Related PR:

• fix(agent): initialize plugins before resolving config #25466 - "fix(agent): initialize plugins before resolving config"
  • This PR also addresses plugin initialization and agent-related issues. It may be related to the plugin registration flow that PR Fix plugin agent registration issue #25505 is fixing.

The search results primarily return PR #25505 (the current PR) itself, which indicates this is a unique fix. The only other potentially related PR is #25466, which deals with plugin initialization sequencing.

No clear duplicate PRs found - this appears to be addressing a specific plugin agent registration bug without direct overlaps in scope.

[rekram1-node]

already fixed, thanks for helping tho