docs: Add opencode-synced plugin to ecosystem documentation

[iHildy]

Summary

Adds opencode-synced to the ecosystem page.

opencode-synced is a plugin that enables syncing global opencode configurations across machines

Features:

• Private and Public options of config visibility (forced private in certian situations)
• Easily pull and push your config changes with commands (ex: /sync-status)

Example use case: Easily have plugin, auth, mcp, agent, etc parity between your local machine and a VPS when you use opencode on both.

[github-actions]

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

No duplicate PRs found.

The searches returned only PR #7001 (the current PR) and one unrelated PR (#5717 about OAuth handling), which is not related to the ecosystem documentation addition.

This appears to be a unique PR adding the opencode-synced plugin to the ecosystem documentation with no existing duplicates or related open PRs addressing the same feature.

[github-actions]

Hey! Your PR title Add opencode-synced plugin to ecosystem documentation 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.