[codex] Restore CAS runtime slash commands

[zeolenon]

What changed

• Declares CAS runtime slash command activation metadata in openclaw.plugin.json.
• Adds manifest commandAliases for the plugin-owned /cas_* commands so newer OpenClaw cores can route them through the plugin command path.
• Includes the beta verbose progress controls and exposes /cas_verbose through the same runtime slash command metadata.

Why

OpenClaw 2026.5.x uses plugin manifest metadata to discover and route runtime slash commands. Without the explicit activation hints and command aliases, commands such as /cas_status and /cas_verbose can appear present in docs/config but fail to route to the Codex app-server plugin.

Validation

• pnpm typecheck
• pnpm test
• pnpm pack:smoke
• Local OpenClaw 2026.5.4 smoke: gateway commands.list exposes /cas_verbose, plugin registration reports hasCasVerbose=true, and Codex/Gemini post-update agent smokes pass.