`DEV_MODE` does not actually disable gateway token use in container (Behavior mismatch)

`MOLTBOT_GATEWAY_TOKEN` is treated as required, which blocks the documented device‑pairing flow (tokenless) in non‑dev mode. This is a behavior mismatch vs README/wrangler notes.

Setting `DEV_MODE=true` is supposed to skip auth/device pairing and allow insecure access. However, the worker still passes `MOLTBOT_GATEWAY_TOKEN` into the container when it’s set, so the gateway starts in token‑auth mode anyway. This makes DEV mode inconsistent with its documented behavior.

See:
- `index.ts`(line 60)
- `wrangler.jsonc`(line 82)

Authentication ▶️ Device Pairing: says “By default, moltbot uses device pairing for authentication” and describes approving devices via /_admin/. This implies tokenless pairing is a valid mode.

Steps to Reproduce:
1. Set `DEV_MODE=true` and also set `MOLTBOT_GATEWAY_TOKEN`
2. Start
3. Connect to the control UI without `?token=`
4. Gateway rejects

Expected Behavior
- In DEV mode, gateway should start without token auth (device pairing/insecure auth), even if a token is present.

Actual Behavior
- DEV mode still passes the token into the container, enabling token auth.