feat: add i18n in login page (#5947)

* feat: add i18n in login page

* fix: add word space and put the app name into the title

* fix: remove duplicate replace title

* fix: prettier format code

* fix: fix typescript check warning

* fix: add zh-cn locale file code owner

* fix: use existing flag locale to the login page

Co-authored-by: Joe Previte <jjprevite@gmail.com>

test/unit/node/routes/login.test.ts

@@ -138,5 +138,16 @@ describe("login", () => {
       expect(resp.status).toBe(200)
       expect(htmlContent).toContain(`Welcome to ${appName}`)
     })
+
+    it("should return correct welcome text when locale is set to non-English", async () => {
+      process.env.PASSWORD = previousEnvPassword
+      const locale = "zh-cn"
+      const codeServer = await integration.setup([`--locale=${locale}`], "")
+      const resp = await codeServer.fetch("/login", { method: "GET" })
+
+      const htmlContent = await resp.text()
+      expect(resp.status).toBe(200)
+      expect(htmlContent).toContain(`欢迎来到 code-server`)
+    })
   })
 })