expand env documentation in generators reference

Author: devalog

fern/products/fern-def/pages/auth.mdx

@@ -3,7 +3,7 @@ title: Authentication
 subtitle: Model auth schemes such as bearer, basic, custom headers, and oauth. 
 ---
 
-Configuring authentication schemes happens in the `api.yml` file. 
+Configuring authentication schemes happens in the `api.yml` file. All Fern-generated SDKs support both direct configuration and environment variables for authentication credentials.
 
 ```bash {5}
 fern/

fern/products/openapi-def/pages/auth.mdx

@@ -3,7 +3,7 @@ title: Authentication
 subtitle: Model auth schemes such as bearer, basic, and api key. 
 ---
 
-Configuring authentication schemes happens in the `components.securitySchemes` section of OpenAPI. 
+Configuring authentication schemes happens in the `components.securitySchemes` section of OpenAPI. All Fern-generated SDKs support both direct configuration and environment variables for authentication credentials.
 
 ```yml title="openapi.yml" {2-3}
 components: 

fern/products/sdks/reference/generators-yml-reference.mdx

@@ -333,7 +333,7 @@ api:
         local-generation: true
 ```
 
-<ParamField path="sproto" type="ProtobufDefinitionSchema" required={true} toc={true}>
+<ParamField path="proto" type="ProtobufDefinitionSchema" required={true} toc={true}>
   Protocol Buffers configuration.
 </ParamField>
 

fern/products/sdks/snippets/basic-auth-params.mdx

@@ -6,10 +6,10 @@ auth-schemes:
     scheme: basic
     username:
       name: "Username"
-      env: "BASIC_AUTH_USERNAME"
+      env: "BASIC_AUTH_USERNAME" # SDK will auto-scan this environment variable
     password:
       name: "Password"
-      env: "BASIC_AUTH_PASSWORD"
+      env: "BASIC_AUTH_PASSWORD" # SDK will auto-scan this environment variable
 ```
 
 <ParamField path="scheme" type="'basic'" required={true}>
@@ -18,18 +18,15 @@ auth-schemes:
 <ParamField path="username" type="object" required={false}>
   Configuration for the username credential.
 </ParamField>
-<ParamField path="name" type="string" required={false}>
-  A descriptive name for the username.
-</ParamField>
-<ParamField path="env" type="string" required={false}>
-  Environment variable name containing the username.
+<ParamField path="username.name" type="string" required={false}>
+  Custom parameter name for the username in the generated SDK. If not specified, defaults to `"username"`. Use this to provide more descriptive or domain-specific parameter names like `"clientId"`, `"userEmail"`, or `"merchantId"`.
 </ParamField>
 <ParamField path="password" type="object" required={false}>
   Configuration for the password credential.
 </ParamField>
-<ParamField path="name" type="string" required={false}>
-  A descriptive name for the password.
+<ParamField path="password.name" type="string" required={false}>
+  Custom parameter name for the password in the generated SDK. If not specified, defaults to `"password"`. Use this to provide more descriptive or domain-specific parameter names like `"clientSecret"`, `"apiKey"`, or `"merchantKey"`.
 </ParamField>
-<ParamField path="env" type="string" required={false}>
-  Environment variable name containing the password.
+<ParamField path="username.env, password.env" type="string" required={false}>
+  Environment variable name that the SDK will automatically scan for the username or password value. When this environment variable is present, users don't need to explicitly provide the username parameter. Follow naming conventions like `YOUR_APP_USERNAME` or `SERVICE_CLIENT_ID`.
 </ParamField>

fern/products/sdks/snippets/bearer-auth-params.mdx

@@ -6,7 +6,7 @@ auth-schemes:
     scheme: bearer
     token:
       name: "Access Token"
-      env: "BEARER_TOKEN"
+      env: "BEARER_TOKEN" # SDK will auto-scan this environment variable
 ```
 
 <ParamField path="scheme" type="'bearer'" required={true}>
@@ -19,5 +19,5 @@ auth-schemes:
   A descriptive name for the token.
 </ParamField>
 <ParamField path="token.env" type="string" required={false}>
-  Environment variable name containing the bearer token.
+  Environment variable name containing the bearer token. When specified, the generated SDK will automatically scan for this environment variable at initialization.
 </ParamField>

fern/products/sdks/snippets/header-auth-params.mdx

@@ -7,7 +7,7 @@ auth-schemes:
     header: "X-API-Key"
     type: "string"
     prefix: "ApiKey "
-    env: "MY_API_KEY"
+    env: "MY_API_KEY" # SDK will auto-scan this environment variable
 ```
 
 <ParamField path="header" type="string" required={true}>
@@ -23,5 +23,5 @@ auth-schemes:
   A prefix to prepend to the header value (e.g., `"Bearer "` or `"Token "`).
 </ParamField>
 <ParamField path="env" type="string" required={false}>
-  Environment variable name containing the authentication value.
+  Environment variable name containing the authentication value. When specified, the generated SDK will automatically scan for this environment variable at initialization.
 </ParamField>

fern/products/sdks/snippets/oauth-params.mdx

@@ -8,8 +8,8 @@ auth-schemes:
     scopes:
       - "read:users"
       - "write:users"
-    client-id-env: "OAUTH_CLIENT_ID"
-    client-secret-env: "OAUTH_CLIENT_SECRET"
+    client-id-env: "OAUTH_CLIENT_ID" # SDK will auto-scan this environment variable
+    client-secret-env: "OAUTH_CLIENT_SECRET" # SDK will auto-scan this environment variable
     token-prefix: "Bearer"
     token-header: "Authorization"
     get-token:
@@ -42,10 +42,10 @@ auth-schemes:
   List of OAuth scopes to request during authentication.
 </ParamField>
 <ParamField path="client-id-env" type="string" required={false}>
-  Environment variable name containing the OAuth client ID.
+  Environment variable name containing the OAuth client ID. When specified, the generated SDK will automatically scan for this environment variable at initialization.
 </ParamField>
 <ParamField path="client-secret-env" type="string" required={false}>
-  Environment variable name containing the OAuth client secret.
+  Environment variable name containing the OAuth client secret. When specified, the generated SDK will automatically scan for this environment variable at initialization.
 </ParamField>
 <ParamField path="token-prefix" type="string" default="Bearer">
   Sets the token header value prefix.