Serve Finance web with Caddy

[iPior]

Summary

• replace the Finance web container runtime from Nginx to caddy:2-alpine
• add a minimal static-only packages/web/Caddyfile with SPA fallback
• remove the obsolete Nginx config and its internal /api reverse proxy

Why

platform-deploy already routes /api/* directly to finance-api:3000 and sends all other Finance traffic to finance-web:80. The app-level Nginx proxy was therefore redundant in production.

This aligns Finance with the current service-auth and template-webapp pattern:

• platform Caddy owns domains, TLS, ingress, and API routing
• the web container Caddy only serves the compiled SPA

Scope

This is intentionally a small runtime-only change. No API, database, auth, Compose, or platform routing behavior is changed.

Validation

• branch is based on current main
• final diff is limited to three web-runtime files
• existing Finance Caddy routing remains compatible with this change