feat: add OpenCode user-level plugin to install command

[imkarrer]

Summary

• Adds a user-level OpenCode plugin (~/.config/opencode/plugins/crg-plugin.ts) that mirrors all three Claude Code hook behaviors: auto-update graph after file edits, show graph status on session start, and detect changes before git commits
• Plugin uses Bun's $ shell API and fails gracefully with try/catch since it's user-level and runs for all projects
• Installed automatically when running install/init with --platform opencode or --platform all, unless --no-hooks is passed

Related Issues & PRs

• Closes [request] Support for OpenCode #36 — implements OpenCode plugin support using the plugins architecture as suggested in the original request
• Related to autoinstaller don't work correctly #182 — that issue reports "OpenCode doesn't detect the plugin" alongside Claude Code hooks format errors; this PR adds a proper global plugin at the documented location (~/.config/opencode/plugins/) which should resolve the OpenCode side of that report
• Related to support for other TUI/IDEs (e.g. OpenCode, VSCode, ..) #59 — extends multi-IDE support beyond MCP config to include native OpenCode plugin integration
• Related to fix: --platform target now filters skills, hooks, and instruction files (#133) #142 — PR fix: --platform target now filters skills, hooks, and instruction files (#133) #142 adds --platform filtering for hooks/skills; this PR respects the same target filtering pattern for the OpenCode plugin

Changes

code_review_graph/skills.py

• _opencode_plugin_content() — returns TypeScript plugin source as a string, hooking into file.edited, session.created, and tool.execute.before events
• install_opencode_plugin() — writes ~/.config/opencode/plugins/crg-plugin.ts, creating directories as needed

code_review_graph/cli.py

• Calls install_opencode_plugin() in _handle_init() when target is all or opencode, gated by --no-hooks
• Added logger module-level variable for consistent logging

tests/test_skills.py

• 16 new tests across 2 test classes:
  • TestOpenCodePluginContent (8 tests): plugin content validation, event hooks, try/catch coverage, TypeScript structure
  • TestInstallOpenCodePlugin (8 tests): file creation, directory creation, overwrite behavior, idempotency, file integrity

Plugin Behaviors

OpenCode Event	Behavior
file.edited	Runs code-review-graph update --skip-flows
session.created	Runs code-review-graph status and logs output
tool.execute.before (when command matches git commit)	Runs code-review-graph detect-changes --brief and logs output

Testing

All 45 tests pass (29 existing + 16 new). Ruff and mypy clean.

Checklist (per CONTRIBUTING.md)

• Feature branch: feature/opencode-plugin
• Tests added for new functionality (16 new tests)
• All tests pass: uv run pytest tests/test_skills.py (45/45)
• Linting passes: ruff check with rules E, F, I, N, W
• Type checking passes: mypy --ignore-missing-imports --no-strict-optional
• Line length ≤ 100 characters
• Python 3.10+ compatible

[tirth8205]

The OpenCode plugin is well-implemented. The TypeScript plugin correctly hooks into file.edited, session.created, and tool.execute.before events, uses try/catch throughout for graceful failure, and the install_opencode_plugin() function is idempotent (overwrites the file since the plugin is self-contained). The 16 tests in TestOpenCodePluginContent and TestInstallOpenCodePlugin provide thorough coverage.

The branch has merge conflicts with main (in code_review_graph/skills.py — the same file was modified by recently merged PRs). Please rebase onto main and resolve the conflicts. The OpenCode plugin section is appended at the end of skills.py, so this should be a clean resolution.

Once rebased, this is ready to merge.

[tirth8205]

Skipping auto-merge: after #142 (platform target filters) landed on main, this branch now conflicts on code_review_graph/cli.py, code_review_graph/skills.py, and tests/test_skills.py. Please rebase and resolve — the conflict is in the platform dict and install CLI glue.