Config permissions/agents overrides cannot override built-in agent policies (external_directory always asks)

Summary

Config-based YOLO / auto-approve does not work in opencode2 beta: setting permissions (V2 array) and agents.<id>.permissions to allow does not override built-in agent policies, so external_directory access still requires approval (ask) even with an allow-all rule.

Environment

• opencode version: 0.0.0-beta-17728
• OS: Linux 7.0.0-29-generic (Ubuntu) x86_64
• Terminal: TERM_PROGRAM=Orca TERM=xterm-256color COLORTERM=truecolor
• Shell: /bin/bash
• Install/channel: beta
• Server: background service http://0.0.0.0:49374
• Config: ~/.config/opencode/opencode.json

Reproduction

1. Add the following to the global config:

{
  "$schema": "https://opencode.ai/config.json",
  "permissions": [{ "action": "*", "resource": "*", "effect": "allow" }],
  "agents": {
    "build": {
      "permissions": [{ "action": "external_directory", "resource": "*", "effect": "allow" }]
    }
  }
}

2. Restart the server: opencode2 service restart
3. Run: opencode2 run -m <model> "read /etc/hostname"
4. Result: permission is still requested

! permission requested: external_directory (/etc/*); auto-rejecting
Read /etc/hostname failed
The user declined this tool call

Expected Behavior

An allow-all rule (global or per-agent) should allow all tool actions including external directory access, so no permission prompt appears.

Actual Behavior

External directory access still asks. The built-in external_directory: ask policy wins over the user's allow rules.

Root Cause Analysis

1. The permissions array IS parsed: opencode2 debug agents shows {action: "*", resource: "*", effect: "allow"} at the start of every agent's effective permission array.
2. V2 permission evaluation uses "last matching rule wins" (findLast). The built-in agent policy rule {external_directory, *, ask} appears AFTER the user's allow-all, so it wins and the request is rejected/asked.
3. agents.<id>.permissions config overrides are NOT appended: debug agents output shows they are missing from the end of the built-in agents' permission arrays.
4. Source: the agent builder reads cfg.agent (singular) but the config schema field is agents (plural), with no conversion — so JSON-configured agent overrides are ignored in this beta.

Suggested Fix

• Convert the V2 agents field into the agent object used by the agent builder (packages/opencode/src/agent/agent.ts), or make the builder read the plural field
• Or ensure user-specified agent rules are appended after built-in policies so they can override them

Workarounds

• CLI: opencode2 run --auto / --yolo (client sends "once" for permission requests) — works
• Web UI: click "Always allow" per project (manual)

Related known issues

• #9661/#21119 Web Revert/Fork actions missing/broken over the versions (web client session/state issues)