acp: custom providers fail to load due to SchemaError(Missing key at ["path"]) on event subscription

Summary

In opencode acp on versions 2.0.6 and 2.0.7, the internal event subscriber crashes with an unhandled schema error (SchemaError: Missing key at ["path"]) during startup. As a consequence, custom providers configured in user settings (opencode.jsonc) are never merged into the ACP session catalog, leaving only built-in fallback models (opencode/*) and causing ACP clients (such as Obsidian's Claudian) to fail with model not found.

Environment

• opencode version: 2.0.6, 2.0.7 (works correctly on 2.0.3)
• OS: macOS (Darwin 25.5.0, arm64)
• Shell: /bin/zsh
• Install: npm global (@opencode/cli)

Reproduction

1. Configure custom models/providers under provider in ~/.config/opencode/opencode.jsonc.
2. Start the ACP server:

   opencode acp --log-level all --print-logs
   

3. Send standard JSON-RPC initialize followed by session/new with mcpServers: [].
4. Inspect the returned configOptions for model and review stderr logs.

Expected Behavior

session/new options should include custom models from opencode.jsonc, and incoming location events (provider.updated, model.updated) should be decoded without schema errors.

Actual Behavior

During boot, right after event.type=command.updated, the CLI process encounters an unhandled rejection:

level=ERROR message="unhandled rejection" cause="SchemaError(Missing key at [\"path\"])" role=cli

Because of this rejection, ACP caches only the initial fallback models (opencode/union-alpha, etc.). Requesting any custom model via session/set_config_option fails with:

{
  "code": -32602,
  "message": "Invalid params: model not found: <custom-provider>/<model>"
}

Additional Context

• Tested in an isolated sandbox on version 2.0.3: custom providers load cleanly over ACP and session/set_config_option succeeds.
• Tested on 2.0.6 and 2.0.7: both fail with the identical SchemaError stack.