Make dev server bind env-driven via HOST/PORT

Replace hardcoded 192.168.1.21 with HOST/PORT env vars loaded from .env
by Foreman. Adds .env.sample template and updates docs accordingly.

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

Author: dadachi

.env.sample

@@ -0,0 +1,6 @@
+# Copy to .env and edit. Loaded by Foreman when running `bin/dev`.
+
+# Rails server bind address and port. Use your LAN IP (e.g. 192.168.1.6) for
+# mobile-device-on-LAN access; use 127.0.0.1 for loopback-only dev.
+HOST=127.0.0.1
+PORT=3000

.gitignore

@@ -10,6 +10,7 @@
 # Ignore all environment files (except templates).
 /.env*
 !/.env*.erb
+!/.env.sample
 
 # Ignore all logfiles and tempfiles.
 /log/*

CLAUDE.md

@@ -96,7 +96,7 @@ bin/rails dbconsole           # Database console
 - Run tests: `bin/rails test` (205 tests, 402 assertions)
 
 ### Development Server Configuration
-- Server binds to specific IP: `192.168.1.21:3000` (not localhost)
+- Server bind and mailer host are env-driven via `HOST`/`PORT` in `.env` (defaults `127.0.0.1:3000`)
 - Mailbin for email testing at `/mailbin`
 - Admin interface at `/madmin`
 - Tailwind CSS compiled by tailwindcss-rails gem

Procfile.dev

@@ -1 +1 @@
-web: bin/rails server -p $PORT -b 192.168.1.21
+web: bin/rails server -p ${PORT:-3000} -b ${HOST:-127.0.0.1}

README.md

@@ -85,7 +85,7 @@ bin/setup
 
 ## Running NativeAppTemplate API on localhost
 
-Replace the IP address `192.168.1.21` with your localhost IP address in `Procfile.dev` and `config/environments/development.rb`.
+Copy `.env.sample` to `.env` and set `HOST` (and optionally `PORT`) to control the server bind address and mailer URL host. Defaults to `127.0.0.1:3000`. For mobile-device-on-LAN access, set `HOST=<your-lan-ip>`. Foreman auto-loads `.env` under `bin/dev`.
 
 To run your application, you'll use the `bin/dev` command:
 

config/environments/development.rb

@@ -38,7 +38,7 @@
 
   config.action_mailer.perform_caching = false
 
-  config.action_mailer.default_url_options = {host: "192.168.1.21", port: ENV.fetch("PORT", 3000).to_i}
+  config.action_mailer.default_url_options = {host: ENV.fetch("HOST", "127.0.0.1"), port: ENV.fetch("PORT", 3000).to_i}
 
   # Print deprecation notices to the Rails logger.
   config.active_support.deprecation = :log