[codex] park side packages, expand native api, and hide /agent

[Gan-Xing]

What changed

• parked codex-gateway and mission-control in the docs and clarified that codex-native-api is the only retained future package path
• expanded codex-native-api toward a more standalone npm package with package-local CLI, daemon management, default provider bootstrap, and broader responses/web-search handling
• hid the unfinished /agent command from user-facing help and aliases, blocked direct invocation by default, and disabled related background scheduling and notifications unless explicitly re-enabled

Why it changed

• the bridge scope has drifted away from the core WeChat plus Codex goal, so the side package status needed to be made explicit
• codex-native-api needed a stronger standalone surface before any future packaging decision
• /agent is not ready for end users yet, so it should stop showing up in discovery paths or leaking through nearby command flows

Impact

• users no longer see or use /agent in normal bridge sessions
• tests keep /agent available by default through the test runner flag so existing agent coverage remains intact
• documentation now reflects the paused package direction more clearly

Root cause

• /agent was still wired into the live help catalog, alias map, and background runtime even though the command is not production-ready

Validation

• git diff --check
• node ./scripts/test.mjs --test-name-pattern="/helps lists all supported slash commands and help entrypoints|/helps renders English help text when locale is set to en|/agent stays hidden and unavailable when the command flag is disabled|/review natural language can reject execution requests and avoids starting review" test/core/bridge_coordinator.test.ts
• node ./scripts/test.mjs --test-name-pattern="WeixinBridgeRuntime prefers supervision-backed agent scheduling and does not double-dispatch the same mission|WeixinBridgeRuntime skips agent supervision when the command is disabled" test/runtime/weixin_bridge_runtime.test.ts

Notes

• the full node ./scripts/test.mjs test/core/bridge_coordinator.test.ts test/runtime/weixin_bridge_runtime.test.ts suite still has three pre-existing /as assertions that assume UTC output instead of the current Africa/Abidjan locale