refactor(hub): 手搓 agent loop 换成 Vercel AI SDK

将 provider/runner/tools 三件手搓轮子替换为 AI SDK v7 的 generateText + tool:
- 删 openrouter-provider.ts(翻译层消失)、provider.ts 自定义消息类型
- runner.ts 循环体改为 generateText({stopWhen: stepCountIs}),保留 RunRequest/RunResult 公共签名
- tools.ts ToolRegistry 改为 ToolFactory + build(ctx, names?) 按 role 白名单构建 tools record
- workspace/cph/feishu 工具改写为 tool() 定义,execute 闭包捕获 per-run ToolContext
- transcript.ts 改为 ModelMessage[] JSONL(0.0.0 cutover,无迁移)
- server.ts/trigger.ts 接 modelFactory + toolWhitelist
- 测试:helpers 写 MockLanguageModel implements LanguageModelV4;5 个测试改写 + 新增 runner.test.ts
- 移除未使用的 openai 依赖
- ADR-0017 Consequences 同步:loop 委托给 AI SDK,provider seam 是 LanguageModel

tsc 干净,54 tests 全过。

hub/src/agent/workspace.ts

@@ -1,16 +1,17 @@
 /**
- * Workspace file tools — bounded read/write/list against the project's
+ * Workspace file tools - bounded read/write/list against the project's
  * curriculum engineering-file tree (ADR-0007 directory tree).
  *
  * All paths are **confined to `ctx.workspaceDir`**: the handler resolves the
  * requested relative path against the workspace root and rejects any path that
  * escapes it (via `..` or absolute paths). This is the agent's only file
- * surface — there is no general bash escape hatch, by design (the Hub agent is
- * narrower than a general "Claude Code").
+ * surface; the Hub agent is narrower than a general coding agent.
  */
 import { readFile, writeFile, readdir, mkdir } from "node:fs/promises";
 import { join, resolve, relative, isAbsolute } from "node:path";
-import type { RegisteredTool } from "./tools.js";
+import { tool } from "ai";
+import { z } from "zod";
+import type { ToolContext, ToolDefinition } from "./tools.js";
 
 /** Thrown when a requested path escapes the project workspace root. */
 export class PathEscape extends Error {
@@ -38,68 +39,42 @@ function confine(requestedPath: string, workspaceDir: string): string {
   return resolved;
 }
 
-interface ReadFileArgs {
-  readonly path: string;
-}
-
-export function readFileTool(): RegisteredTool {
-  return {
-    spec: {
-      name: "read_file",
-      description: "Read a file from the project's curriculum engineering-file workspace. Path is relative to the workspace root.",
-      parameters: {
-        type: "object",
-        properties: { path: { type: "string", description: "Relative path within the workspace." } },
-        required: ["path"],
-      },
-    },
-    async execute(args, ctx): Promise<string> {
-      const a = args as ReadFileArgs;
+export function readFileTool(ctx: ToolContext): ToolDefinition {
+  return tool({
+    description: "Read a file from the project's curriculum engineering-file workspace. Path is relative to the workspace root.",
+    inputSchema: z.object({
+      path: z.string().describe("Relative path within the workspace."),
+    }),
+    execute: async (args): Promise<string> => {
       try {
-        const full = confine(a.path, ctx.workspaceDir);
+        const full = confine(args.path, ctx.workspaceDir);
         return await readFile(full, "utf8");
       } catch (e) {
         return JSON.stringify({ error: e instanceof Error ? e.message : String(e) });
       }
     },
-  };
+  });
 }
 
-interface WriteFileArgs {
-  readonly path: string;
-  readonly content: string;
-}
-
-export function writeFileTool(): RegisteredTool {
-  return {
-    spec: {
-      name: "write_file",
-      description: "Write a file in the project's curriculum engineering-file workspace. Path is relative to the workspace root. Creates parent directories.",
-      parameters: {
-        type: "object",
-        properties: {
-          path: { type: "string", description: "Relative path within the workspace." },
-          content: { type: "string", description: "The full file content to write." },
-        },
-        required: ["path", "content"],
-      },
-    },
-    async execute(args, ctx): Promise<string> {
-      const a = args as WriteFileArgs;
+export function writeFileTool(ctx: ToolContext): ToolDefinition {
+  return tool({
+    description:
+      "Write a file in the project's curriculum engineering-file workspace. Path is relative to the workspace root. Creates parent directories.",
+    inputSchema: z.object({
+      path: z.string().describe("Relative path within the workspace."),
+      content: z.string().describe("The full file content to write."),
+    }),
+    execute: async (args): Promise<string> => {
       try {
-        const full = confine(a.path, ctx.workspaceDir);
+        const full = confine(args.path, ctx.workspaceDir);
         await mkdir(join(full, ".."), { recursive: true });
-        await writeFile(full, a.content, "utf8");
-        return JSON.stringify({ ok: true, path: a.path, bytes: a.content.length });
+        await writeFile(full, args.content, "utf8");
+        return JSON.stringify({ ok: true, path: args.path, bytes: args.content.length });
       } catch (e) {
         return JSON.stringify({ error: e instanceof Error ? e.message : String(e) });
       }
     },
-  };
-}
-
-interface ListFilesArgs {
-  readonly path?: string;
+  });
 }
 
 interface Entry {
@@ -107,19 +82,14 @@ interface Entry {
   readonly kind: "file" | "dir";
 }
 
-export function listFilesTool(): RegisteredTool {
-  return {
-    spec: {
-      name: "list_files",
-      description: "List files and directories at a path within the workspace. Defaults to the workspace root.",
-      parameters: {
-        type: "object",
-        properties: { path: { type: "string", description: "Relative path within the workspace; defaults to root." } },
-      },
-    },
-    async execute(args, ctx): Promise<string> {
-      const a = (args as ListFilesArgs) ?? {};
-      const sub = a.path ?? ".";
+export function listFilesTool(ctx: ToolContext): ToolDefinition {
+  return tool({
+    description: "List files and directories at a path within the workspace. Defaults to the workspace root.",
+    inputSchema: z.object({
+      path: z.string().describe("Relative path within the workspace; defaults to root.").optional(),
+    }),
+    execute: async (args): Promise<string> => {
+      const sub = args.path ?? ".";
       try {
         const full = confine(sub, ctx.workspaceDir);
         const entries = await readdir(full, { withFileTypes: true });
@@ -132,5 +102,5 @@ export function listFilesTool(): RegisteredTool {
         return JSON.stringify({ error: e instanceof Error ? e.message : String(e) });
       }
     },
-  };
+  });
 }