Bootstrap Client IP

Add a ClientIP module to a Phoenix 1.8 app that resolves the real client IP address from reverse proxy headers, with configurable trusted proxy ranges and a conn-assigning plug.

What Gets Created/Configured

1. lib/_web/client_ip.ex — Core module that extracts real IP from proxy headers
2. lib/_web/plugs/client_ip.ex — Plug that assigns :client_ip to conn
3. config/config.exs — Default trusted proxy config and header priority
4. config/runtime.exs — Production trusted proxy config via env var (optional)

App Name Detection

Detect from mix.exs:

• App module prefix (e.g., MyApp) — the module namespace
• OTP app name (e.g., :my_app) — used in config atoms
• Web module prefix (e.g., MyAppWeb) — for web module references