👷 update pinned proxy translation for Playwright 1.59

- Refresh comments to reference 1.59 client and v1.59.1 protocol diff.
- Translate Browser initializer: populate `browserName` from legacy `name`
  field, which 1.59 now requires on BrowserInitializer.

Author: thomas-lebeau

test/e2e/scripts/pinnedProxy.ts

@@ -1,15 +1,15 @@
-// WebSocket translation proxy that lets a recent @playwright/test client (1.58) drive an
+// WebSocket translation proxy that lets a recent @playwright/test client (1.59) drive an
 // older `playwright run-server` (1.40). Two layers of translation:
 //
 // 1) HTTP upgrade — the 1.40 server's User-Agent version check rejects mismatched clients
 //    with HTTP 428. We rewrite the upgrade request's User-Agent so the check passes.
 //
-// 2) JSON-RPC — once connected, the 1.58 client validates server messages strictly and
-//    sends commands using the 1.58 schema. We patch __create__ initializers (server→client)
+// 2) JSON-RPC — once connected, the recent client validates server messages strictly and
+//    sends commands using the recent schema. We patch __create__ initializers (server→client)
 //    and command parameters (client→server) where the schemas diverge between versions.
 //
 // Patches were derived from a diff of packages/protocol/src/protocol.yml between v1.40.1
-// and v1.58.2 — only the divergences exercised by this repo's e2e tests are translated.
+// and v1.59.1 — only the divergences exercised by this repo's e2e tests are translated.
 //
 // Usage: node pinnedProxy.ts --listen 5400 --upstream 127.0.0.1:5401
 
@@ -171,6 +171,11 @@ function rewriteServerToClient(text: string, guidTypes: Map<string, string>): st
     if (type === 'Request' && init.hasResponse === undefined) {
       init.hasResponse = false
     }
+    // BrowserInitializer requires `browserName` in 1.59. In 1.40 the `name` field already
+    // held the browser type ("chromium" | "firefox" | "webkit"), so copy it over.
+    if (type === 'Browser' && init.browserName === undefined && typeof init.name === 'string') {
+      init.browserName = init.name
+    }
     msg.params.initializer = init
   }
   return JSON.stringify(msg)