feat(admin): rewrite the admin panel copy in plain words

Labels are two to four words, descriptions one short line, and the
wording follows the reader rather than the implementation: "服务商"
instead of "provider", "本页设置" instead of "后台设置" for the source
chip (it shared its name with the page title), "需重启" as a badge, a
verb on every switch ("访问内网"), "Langfuse 密钥" instead of "私钥".
Descriptions keep the facts the old ones had (where to change an
env-managed provider, that users must enter an access code), and the
same style is applied to the English, Japanese and Traditional Chinese
dictionaries. Five user-facing strings in the same files are aligned
with the new terms (服务商, token).

app/api/chat/route.ts

@@ -98,11 +98,6 @@ function createCachedStreamResponse(xml: string): Response {
 
 // Responses streamed from the model, whose trace streamText's callbacks end
 const modelStreamResponses = new WeakSet<Response>()
-// A Request's signal follows the client's disconnect only while the Request
-// object itself is alive: once it is garbage collected, the abort is lost
-// (nodejs/undici#3644) and a stopped chat would run on at the provider.
-// Each request is kept as long as its answer streams.
-const requestOfResponse = new WeakMap<Response, Request>()
 
 // Inner handler function
 const DEBUG_LLM_PAYLOAD = process.env.DEBUG_LLM_PAYLOAD === "true"
@@ -792,7 +787,6 @@ Call this tool to get shape names and usage syntax for a specific library.`,
         },
     })
     modelStreamResponses.add(response)
-    requestOfResponse.set(response, req)
     return response
 }