The 'port with available port starts server' test was calling
createOpencode from the SDK which spawns an actual opencode binary.
CI environments don't have opencode installed, causing ENOENT.
Mock @opencode-ai/sdk and port-utils (same pattern as
server-connection.test.ts) so the test verifies integration
logic without requiring the binary.
Implement all 5 CLI extension options for external orchestration:
- --port <port>: Start server on port, or attach if port occupied
- --attach <url>: Connect to existing opencode server
- --session-id <id>: Resume existing session instead of creating new
- --on-complete <command>: Execute shell command with env vars on completion
- --json: Output structured RunResult JSON to stdout
Refactor runner.ts into focused modules:
- agent-resolver.ts: Agent resolution logic
- server-connection.ts: Server connection management
- session-resolver.ts: Session create/resume with retry
- json-output.ts: Stdout redirect + JSON emission
- on-complete-hook.ts: Shell command execution with env vars
Fixes#1586