fix: move newsfeed-api off 8081 to 22672 (conflict-unlikely port)

8081 is the alt-HTTP port — one of the crowded defaults every proxy/dev server
grabs — so it's collision-prone on a shared host. Move to 22672, a registered-
range port in the sparse 20000s band, derived deterministically from the
service name and recorded in architecture port-allocations.md.

Updated everywhere the number appears: api bind config + default, firewalld
service XML, nginx upstream, vite dev proxy, deploy workflow API_PORT,
infra-setup (SELinux semanage label), and docs.

Operator note: re-run script/infra-setup.sh on slartibartfast to relabel the
SELinux port (22672) and ship the updated firewalld XML before the next deploy
restarts the api on the new port.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016fKZzDpvjiJ9eYbPGgJvUP

web/vite.config.ts

@@ -9,8 +9,8 @@ export default defineConfig({
   server: {
     port: 5173,
     proxy: {
-      '/v1': 'http://127.0.0.1:8081',
-      '/health': 'http://127.0.0.1:8081',
+      '/v1': 'http://127.0.0.1:22672',
+      '/health': 'http://127.0.0.1:22672',
     },
   },
   build: {