docs: opencode-shell-strategy plugin to ecosystem

[JRedeker]

Summary

Adds opencode-shell-strategy to the Plugins section of the ecosystem page.

About the Plugin

Instructions file that teaches LLMs how to avoid interactive shell commands that hang in OpenCode's non-TTY environment.

Covers:

• Package managers: npm init -y, apt-get install -y, pip install --no-input
• Git operations: git commit -m, git merge --no-edit, avoid git add -p
• System commands: rm -f, ssh -o BatchMode=yes, unzip -o
• Banned commands: editors (vim, nano), pagers (less, more, man)

This is particularly useful for models less familiar with headless CI/CD environments.

Checklist

• Entry added alphabetically in the Plugins table
• Link points to valid GitHub repository
• Description is concise and accurate

[JRedeker]

Update: The shell-strategy instructions have been significantly expanded to include:

• Environment variables section (12 auto-set vars like CI, GIT_TERMINAL_PROMPT, npm_config_yes, etc.)
• Additional package managers: Yarn, PNPM, Bun, Homebrew
• Docker patterns: Avoiding -it flags that hang
• Python/Node REPL guidance
• SSH with StrictHostKeyChecking
• Git --no-pager for log/diff commands
• Timeout wrapper as a last resort
• Best practices section

The file grew from ~55 lines to ~140 lines of comprehensive coverage.