dev-env(proxmox): switch compose to direct-port exposure; document homelab topology

- docker-compose.dev.yml: drop Traefik/dev.resolutionflow.com labels, expose
  backend:8000 and frontend:5173 directly; swap relative bind mounts for
  ${REPO_ROOT}/... so compose works when driven from inside a code-server
  container with the host Docker socket mounted; default POSTGRES_PORT to
  5433 host-side; add explicit uvicorn/npm run dev commands; add
  ENABLE_MCP_MICROSOFT_LEARN and docker-01/Tailscale CORS origins.
- frontend/vite.config.ts: replace dev.resolutionflow.com with
  allowedHosts=['docker-01', '.ts.net', 'localhost'] for direct-port access
  over the private network.
- DEV-ENV.md: add Section 11 reference topology for the homelab Proxmox +
  code-server Option B setup, plus troubleshooting entries for the
  REPO_ROOT-empty-mount trap and the Vite allowedHosts rejection.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/vite.config.ts

@@ -19,7 +19,7 @@ export default defineConfig({
   ],
   server: {
     host: '0.0.0.0',
-    allowedHosts: ['dev.resolutionflow.com'],
+    allowedHosts: ['docker-01', '.ts.net', 'localhost'],
     watch: {
       usePolling: true,
     },