fix: 修正 logo 中 N 和 G 字母造型

N 添加对角线笔画（█▄ █），G 添加内横杠（█ ▀█），
避免与 O 字母造型雷同。同步更新 ui.ts 中的硬编码 wordmark。

packages/llm/src/providers/github-copilot.ts

@@ -0,0 +1,66 @@
+import { AuthOptions, type ProviderAuthOption } from "../route/auth-options"
+import type { RouteDefaultsInput } from "../route/client"
+import { ProviderID, type ModelID } from "../schema"
+import * as OpenAIChat from "../protocols/openai-chat"
+import * as OpenAIResponses from "../protocols/openai-responses"
+import { withOpenAIOptions, type OpenAIProviderOptionsInput } from "./openai-options"
+
+export const id = ProviderID.make("github-copilot")
+
+// GitHub Copilot has no canonical public URL — callers (opencode, etc.) must
+// supply `baseURL` explicitly.
+export type ModelOptions = Omit<RouteDefaultsInput, "providerOptions"> &
+  ProviderAuthOption<"optional"> & {
+    readonly baseURL: string
+    readonly providerOptions?: OpenAIProviderOptionsInput
+  }
+
+export const shouldUseResponsesApi = (modelID: string | ModelID) => {
+  const model = String(modelID)
+  const match = /^gpt-(\d+)/.exec(model)
+  if (!match) return false
+  return Number(match[1]) >= 5 && !model.startsWith("gpt-5-mini")
+}
+
+export const routes = [OpenAIResponses.route, OpenAIChat.route]
+
+const chatRoute = OpenAIChat.route.with({ provider: id })
+const responsesRoute = OpenAIResponses.route.with({ provider: id })
+
+const defaults = (options: ModelOptions) => {
+  const { apiKey: _, auth: _auth, baseURL: _baseURL, ...rest } = options
+  return rest
+}
+
+const configuredResponsesRoute = (options: ModelOptions) =>
+  responsesRoute.with({
+    endpoint: { baseURL: options.baseURL },
+    auth: AuthOptions.bearer(options, []),
+  })
+
+const configuredChatRoute = (options: ModelOptions) =>
+  chatRoute.with({
+    endpoint: { baseURL: options.baseURL },
+    auth: AuthOptions.bearer(options, []),
+  })
+
+export const configure = (options: ModelOptions) => {
+  const responsesRoute = configuredResponsesRoute(options)
+  const chatRoute = configuredChatRoute(options)
+  const responses = (modelID: string | ModelID) =>
+    responsesRoute.with(withOpenAIOptions(modelID, defaults(options))).model({ id: modelID })
+  const chat = (modelID: string | ModelID) =>
+    chatRoute.with(withOpenAIOptions(modelID, defaults(options))).model({ id: modelID })
+  return {
+    id,
+    model: (modelID: string | ModelID) => (shouldUseResponsesApi(modelID) ? responses(modelID) : chat(modelID)),
+    responses,
+    chat,
+    configure,
+  }
+}
+
+export const provider = {
+  id,
+  configure,
+}