docs: add info to .env.example to explain what is needed where

.env.example

@@ -1,14 +1,24 @@
+# The following are configured in the .env.production and .env.development
+# files, you should not have to change them. If you do, please do NOT commit
+# those changes
 NEXT_PUBLIC_VERCEL_ENV = development
+NEXT_PUBLIC_URL = 'http://localhost:3000'
+NEXT_PUBLIC_MOD_PROTOCOL_API_URL = 'https://api.modprotocol.org/api'
+
+# The following are sensative data and should
+# be stored in a .env.development.local file
+# for local development, and are hosted in Vercel
+# for production use cases
 NEXT_PUBLIC_APP_FID = '123'
 NEXT_PUBLIC_APP_MNENOMIC = 'candy maple cake sugar honey ... potato blue'
 NEXT_PUBLIC_SUPABASE_URL = ''
 NEXT_PUBLIC_SUPABASE_ANON_KEY = ''
 NEXT_PUBLIC_NEYNAR_API_KEY = ''
-NEXT_PUBLIC_SENTRY_DSN = ''
-NEXT_PUBLIC_URL = 'http://localhost:3000'
-
-NEXT_PUBLIC_MOD_PROTOCOL_API_URL = 'https://api.modprotocol.org/api'
+NEXT_PUBLIC_ALCHEMY_API_KEY=''
 
+# The following are required for tracking
+# and deployment purposes. They are also sensative
+# but not required for local development
+NEXT_PUBLIC_SENTRY_DSN = ''
 NEXT_PUBLIC_POSTHOG_KEY=
 NEXT_PUBLIC_POSTHOG_HOST=
-NEXT_PUBLIC_ALCHEMY_API_KEY=