Add documentation for environment variable exclusion

Author: ostenbom

src/content/docs/reference/endform-config-ts.md

@@ -85,6 +85,18 @@ By default the following environment variables are automatically transferred:
 - Environment variables that start with `E2E_`
 - All environment variables that are set in your `playwright.config.ts`
 
+#### Excluding environment variables
+
+Prefix a pattern with `!` to exclude matching environment variables, including ones that would be transferred automatically:
+
+```ts
+import { defineEndformConfig } from "endform";
+
+export default defineEndformConfig({
+  environmentVariables: ["!^PLAYWRIGHT_BDD_CONFIGS$"],
+});
+```
+
 ### `extraHttpHeaders`
 
 Set extra HTTP headers that will be applied to the Playwright browser contexts when tests run on remote runners. The value is an object mapping header names to string values.

src/content/docs/reference/endform-config.md

@@ -84,6 +84,16 @@ By default the following environment variables are automatically transferred:
 - Environment variables that start with `E2E_`
 - All environment variables that are set in your `playwright.config.ts`
 
+#### Excluding environment variables
+
+Prefix a pattern with `!` to exclude matching environment variables, including ones that would be transferred automatically:
+
+```json
+{
+  "environmentVariables": ["!^PLAYWRIGHT_BDD_CONFIGS$"]
+}
+```
+
 ### `extraHttpHeaders`
 
 Set extra HTTP headers that will be applied to the Playwright browser contexts when tests run on remote runners. The value is a JSON object mapping header names to string values.

src/content/docs/reference/environment-variables.md

@@ -14,6 +14,7 @@ At a high level:
 - `E2E_*` variables are transferred automatically.
 - Variables referenced from tests via `process.env` are transferred automatically.
 - You can explicitly include additional variables with `environmentVariables`.
+- You can exclude variables with `!`-prefixed patterns in `environmentVariables`, for example `"!^PLAYWRIGHT_BDD_CONFIGS$"`. Exclusions take precedence over everything above.
 
 ## Runtime marker: `ENDFORM=true`