Remove insecure NODE_TLS_REJECT_UNAUTHORIZED=0 TLS workaround

The MeshMonitor gateway uses a valid Let's Encrypt certificate, so
standard TLS certificate verification already works — no workaround
needed. The flag was a security downgrade: it disabled cert verification
for ALL outbound connections in the container (including the LLM and
opencode services), not just the gateway.

- docker-compose.yml: drop NODE_TLS_REJECT_UNAUTHORIZED env line + comment
- src/main.ts: drop process.env.NODE_TLS_REJECT_UNAUTHORIZED + comments
- CHANGELOG.md: correct the v0.22.0 Docker bullet wording

Part of the already-open MeshMonitor connection work (PR #56): no version
bump, no new changelog section.

Co-Authored-By: OpenCode <noreply@opencode.ai>

src/main.ts

@@ -6,10 +6,6 @@ import { apiReference } from '@scalar/nestjs-api-reference';
 import * as pkg from '../package.json';
 import { AppModule } from './app.module.js';
 
-// the MeshMonitor gateway (https://meshmonitor.kkhost.pl) uses a self-signed certificate — accept it
-// (compose sets the same variable for the deployed stack; this covers local runs too)
-process.env.NODE_TLS_REJECT_UNAUTHORIZED = '0';
-
 async function bootstrap() {
   const app = await NestFactory.create<NestExpressApplication>(AppModule);
   app.enableShutdownHooks();