OpenCode E2E tests

[Soph]

Adding OpenCode E2E tests

[cursor]

PR Summary

Medium Risk
Adds a new external-agent execution path (opencode) and changes OpenCode hook dispatch to run synchronously at session/turn end, which can affect shutdown timing and E2E stability across environments.

Overview
Adds OpenCode as a supported E2E test agent by introducing an OpenCodeRunner that invokes opencode run, wiring it into the NewAgentRunner factory, and adding a dedicated mise task (test:e2e:opencode).

Hardens the OpenCode Entire plugin by switching turn-end detection from deprecated session.idle to session.status (idle) and running turn-end/session-end hooks synchronously via Bun.spawnSync to ensure hooks complete before opencode run exits. Also updates E2E repo setup to write opencode.json to allow external_directory permissions in non-interactive mode, and makes minor assertion cleanups (assert.Len).

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[Copilot]

Pull request overview

This pull request adds comprehensive E2E test support for the OpenCode AI coding agent, making it the third agent supported alongside Claude Code and Gemini CLI. The implementation follows the established multi-agent pattern and includes necessary fixes to the OpenCode plugin for reliable hook execution in non-interactive mode.

Changes:

• Added new test:e2e:opencode task to mise.toml for running OpenCode E2E tests
• Implemented OpenCodeRunner following the existing agent runner pattern with proper timeout handling and model configuration
• Fixed OpenCode plugin to use synchronous hook calls for turn-end and session-end events to prevent premature process exit
• Added OpenCode-specific test environment configuration to handle permission settings
• Improved test assertions to use assert.Len instead of assert.Equal for slice length checks

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
mise.toml	Adds E2E test task for OpenCode agent with appropriate timeout and test tags
cmd/entire/cli/e2e_test/testenv.go	Adds OpenCode permission configuration to test environment setup and removes redundant gosec linter directive
cmd/entire/cli/e2e_test/agent_runner.go	Implements OpenCodeRunner following established patterns for agent CLI integration
cmd/entire/cli/agent/opencode/entire_plugin.ts	Migrates from deprecated session.idle to session.status events and adds synchronous hook execution to prevent race conditions
cmd/entire/cli/e2e_test/scenario_checkpoint_workflows_test.go	Improves test assertions to use assert.Len per testifylint best practices

The base branch was changed.