Remove remote reporter configuration docs (#13)

## Summary

- remove the retired `remoteReporters` sections from the JSON and
TypeScript config references
- remove remote reporters from the Playwright performance guide
description
- retain the custom reporters explanation, which already documents local
`merge-reports` execution

## Verification

- `pnpm build`

Author: ostenbom

src/content/docs/guides/tune-playwright-suite-performance.mdx

@@ -1,6 +1,6 @@
 ---
 title: Performance tuning your Playwright suite for Endform
-description: Tune Endform concurrency, network proxying, runner regions, and remote reporters for faster Playwright runs
+description: Tune Endform concurrency, network proxying, and runner regions for faster Playwright runs
 sidebar:
   order: 4
 ---

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

@@ -202,31 +202,3 @@ export default defineEndformConfig({
   region: "eu",
 });
 ```
-
-### `remoteReporters`
-
-An array of reporter names that should run exclusively during remote execution of tests.
-Must correspond to the name of a reporter configured in your Playwright config.
-
-For example, if `endform.config.ts` is:
-```ts
-import { defineEndformConfig } from "endform";
-
-export default defineEndformConfig({
-  remoteReporters: ["./custom-reporter.ts"],
-});
-```
-
-And `playwright.config.ts` is set to:
-```ts
-import { defineConfig, devices } from "@playwright/test";
-
-export default defineConfig({
-  reporter: [
-    ["./custom-reporter.ts", { myCustomReporterOption: true }]
-  ],
-});
-
-```
-
-Then `./custom-reporter.ts` will run once on each remotely running test machine (one per test), and _not_ on the collected result.

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

@@ -156,29 +156,3 @@ Available values are `"eu"` and `"us"`.
   "region": "eu"
 }
 ```
-
-### `remoteReporters`
-
-An array of reporter names that should run exclusively during remote execution of tests.
-Must correspond to the name of a reporter configured in your Playwright config.
-
-For example, if `endform.jsonc` is:
-```json
-{
-  "remoteReporters": ["./custom-reporter.ts"]
-}
-```
-
-And `playwright.config.ts` is set to:
-```ts
-import { defineConfig, devices } from "@playwright/test";
-
-export default defineConfig({
-  reporter: [
-    ["./custom-reporter.ts", { myCustomReporterOption: true }]
-  ],
-});
-
-```
-
-Then `./custom-reporter.ts` will run once on each remotely running test machine (one per test), and _not_ on the collected result.