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/test/schema.test.ts

@@ -0,0 +1,86 @@
+import { describe, expect, test } from "bun:test"
+import { Schema } from "effect"
+import * as OpenAIChat from "../src/protocols/openai-chat"
+import * as OpenAIResponses from "../src/protocols/openai-responses"
+import { ContentPart, LLMEvent, LLMRequest, Model, ModelID, ProviderID, Usage } from "../src/schema"
+import { ProviderShared } from "../src/protocols/shared"
+
+const model = new Model({
+  id: ModelID.make("fake-model"),
+  provider: ProviderID.make("fake-provider"),
+  route: OpenAIChat.route,
+})
+
+const decodeLLMRequest = Schema.decodeUnknownSync(LLMRequest as unknown as Schema.Decoder<LLMRequest>)
+const decodeLLMEvent = Schema.decodeUnknownSync(LLMEvent as unknown as Schema.Decoder<LLMEvent>)
+
+describe("llm schema", () => {
+  test("decodes a minimal request", () => {
+    const input: unknown = {
+      id: "req_1",
+      model,
+      system: [{ type: "text", text: "You are terse." }],
+      messages: [{ role: "user", content: [{ type: "text", text: "hi" }] }],
+      tools: [],
+      generation: {},
+    }
+
+    const decoded = decodeLLMRequest(input)
+
+    expect(decoded.id).toBe("req_1")
+    expect(decoded.messages[0]?.content[0]?.type).toBe("text")
+  })
+
+  test("accepts custom route ids", () => {
+    const decoded = decodeLLMRequest({
+      model: Model.update(model, { route: OpenAIResponses.route }),
+      system: [],
+      messages: [],
+      tools: [],
+      generation: {},
+    })
+
+    expect(decoded.model.route.id).toBe("openai-responses")
+  })
+
+  test("rejects invalid event type", () => {
+    expect(() => decodeLLMEvent({ type: "bogus" })).toThrow()
+  })
+
+  test("finish constructors accept usage input", () => {
+    expect(LLMEvent.stepFinish({ index: 0, reason: "stop", usage: { inputTokens: 1 } }).usage).toBeInstanceOf(Usage)
+    expect(LLMEvent.finish({ reason: "stop", usage: { outputTokens: 2 } }).usage).toBeInstanceOf(Usage)
+  })
+
+  test("content part tagged union exposes guards", () => {
+    expect(ContentPart.guards.text({ type: "text", text: "hi" })).toBe(true)
+    expect(ContentPart.guards.media({ type: "text", text: "hi" })).toBe(false)
+  })
+})
+
+describe("LLM.Usage", () => {
+  test("subtractTokens clamps non-sensical breakdowns to zero", () => {
+    // Defense against a provider reporting cached_tokens > prompt_tokens or
+    // reasoning_tokens > completion_tokens — the negative would otherwise
+    // round-trip through the pipeline and crash strict downstream schemas.
+    expect(ProviderShared.subtractTokens(5, 3)).toBe(2)
+    expect(ProviderShared.subtractTokens(5, 10)).toBe(0)
+    expect(ProviderShared.subtractTokens(5, undefined)).toBe(5)
+    expect(ProviderShared.subtractTokens(undefined, 3)).toBeUndefined()
+    expect(ProviderShared.subtractTokens(undefined, undefined)).toBeUndefined()
+  })
+
+  test("sumTokens returns undefined only when every input is undefined", () => {
+    expect(ProviderShared.sumTokens(1, 2, 3)).toBe(6)
+    expect(ProviderShared.sumTokens(1, undefined, 3)).toBe(4)
+    expect(ProviderShared.sumTokens(undefined, undefined, undefined)).toBeUndefined()
+    expect(ProviderShared.sumTokens()).toBeUndefined()
+  })
+
+  test("visibleOutputTokens clamps reasoning > output to zero", () => {
+    expect(new Usage({ outputTokens: 10, reasoningTokens: 4 }).visibleOutputTokens).toBe(6)
+    expect(new Usage({ outputTokens: 10 }).visibleOutputTokens).toBe(10)
+    expect(new Usage({ outputTokens: 4, reasoningTokens: 10 }).visibleOutputTokens).toBe(0)
+    expect(new Usage({}).visibleOutputTokens).toBe(0)
+  })
+})