bug: Gemini CLI adapter missing --experimental-acp flag, causes ACP initialization hang

[kckylechen1]

Bug Description

When using the Gemini CLI adapter with ACP (Agent Context Protocol), the initialization hangs because the adapter does not pass the required --experimental-acp flag to the underlying Gemini CLI process.

Expected Behavior

The Gemini CLI adapter should include the --experimental-acp flag when invoking the Gemini CLI, enabling proper ACP initialization and protocol handshake.

Actual Behavior

ACP initialization hangs indefinitely, as the Gemini CLI waits for the experimental flag to enable ACP support but never receives it.

Steps to Reproduce

1. Configure acpx to use the Gemini CLI adapter
2. Initialize ACP protocol
3. Observe the hang during initialization

Environment

• acpx version: [current]
• Gemini CLI version: [current]

Proposed Fix

Add the --experimental-acp flag to the command arguments when invoking the Gemini CLI from the adapter.

[saxlamen]

Fixed in PR #52

The issue was that the Gemini CLI adapter in AGENT_REGISTRY didn't include the --experimental-acp flag.

Fix: Changed gemini: "gemini" to gemini: "gemini --experimental-acp" in src/agent-registry.ts.

Verified: After this fix, acpx gemini exec "Say hi" works correctly instead of hanging on initialization.