RFC-030: wire codex-app-server into anet CLI

[vansin]

What changed

• makes codex-app-server an explicit anet node create choice in both TTY
  picker paths and preserves an explicit --runtime codex-app-server flag;
• routes anet node start for every non-Claude-Code runtime through
  agent-node, preventing codex-app-server profiles from falling into the
  Claude CLI launcher;
• adds codex-app-server to anet and agent-node help;
• documents the canonical copy/paste command in RFC-030 and marks the old
  codex-sdk --codex-transport app-server proposal as superseded;
• keeps the capability claim narrow: this starts the Phase-0 direct preview
  path. Policy Gateway, Wave 2, §8, merge, production and latest remain
  locked.

Root cause

Runtime normalization and agent-node already recognized the canonical
codex-app-server value, but the outer anet CLI had two independent
allowlists that omitted it. A TTY create could overwrite the explicit flag,
and start then selected the Claude CLI branch.

Validation

• bun test agent-network/src/normalize-runtime.test.ts — 32 pass, 0 fail;
• both CLI bundles build successfully;
• anet --help and agent-node --help include codex-app-server;
• isolated real-machine smoke passed with a throwaway HOME/project/SQLite Hub:
  • real TTY create wrote runtime: codex-app-server without reopening the
    picker;
  • real built anet node start launched real built
    agent-node --runtime codex-app-server;
  • the node registered successfully on the isolated Hub;
  • no production Hub, deployment, package or latest state was touched.

The smoke proves CLI startup/registration only. It does not exercise or claim
the production Policy Gateway or §8 release gate.