refactor(hub): role 改为数据条目,不再是写死的闭集枚举

ADR-0017 说 role-based routing 是 product/admin config,不是 spec invariant。
之前 RunRole = "draft"|"review"|"triage" 闭集违反这条——role 钉死在代码里,
教师/admin 无法自定义。改为:
- RoleEntry(id+label+defaultModel)是数据,registry 持有 role 集合
- roleId 退化为 string,新 role 是配置改动不是代码改动
- runner 不再带 role 字段(model 已由 caller resolve 好传入,role 透传无意义)
- 未知 role 优雅降级到首个启用 model,不抛
tsc --noEmit rc=0;role-as-data + ADR-0003 不变式 smoke 通过。

hub/src/agent/models.ts

@@ -8,8 +8,20 @@
  * here — decided by admin settings + ADR, not hard-coded.
  */
 
-/** Coarse run role, used to pick a default model. Open set: add as product grows. */
-export type RunRole = "draft" | "review" | "triage";
+/**
+ * A named role preset that maps to a default model. Roles are **data**, not a
+ * code enum: admin/teachers define them (ADR-0017: role-based routing is
+ * product config, not a spec invariant). `roleId` is an opaque string here —
+ * the registry holds the role set, so new roles are added by configuration,
+ * not by editing this file.
+ */
+export interface RoleEntry {
+  readonly id: string;
+  /** Human label for the teacher-side switcher UX. */
+  readonly label: string;
+  /** Default model id for runs under this role, if a routing rule is set. */
+  readonly defaultModel: string | undefined;
+}
 
 /** A model the admin has enabled for use by the Hub. */
 export interface ModelEntry {
@@ -22,41 +34,50 @@ export interface ModelEntry {
 
 export interface ModelRegistry {
   /** All models admin-enabled for this Hub instance. */
-  list(): readonly ModelEntry[];
-  /** Default model id for a given run role, if a routing rule exists. */
-  defaultFor(role: RunRole): string | undefined;
+  listModels(): readonly ModelEntry[];
+  /** All role presets currently configured (admin/teacher-defined). */
+  listRoles(): readonly RoleEntry[];
+  /** The role preset with the given id, if any. */
+  role(id: string): RoleEntry | undefined;
 }
 
 /**
  * A simple in-memory registry. Real wiring reads from admin settings / DB; this
- * is the skeleton seam. The policy (role→model map) is intentionally pluggable.
+ * is the skeleton seam. Both the model list and the role set are pluggable data
+ * — adding a role is a config change, not a code change.
  */
 export class InMemoryModelRegistry implements ModelRegistry {
   private readonly models: readonly ModelEntry[];
-  private readonly defaults: Map<RunRole, string>;
+  private readonly roles: Map<string, RoleEntry>;
 
-  constructor(models: readonly ModelEntry[], defaults: Partial<Record<RunRole, string>> = {}) {
+  constructor(models: readonly ModelEntry[], roles: readonly RoleEntry[] = []) {
     this.models = models;
-    this.defaults = new Map(
-      (Object.entries(defaults) as [RunRole, string][]).filter(([, v]) => v !== undefined),
-    );
+    this.roles = new Map(roles.map((r) => [r.id, r]));
   }
 
-  list(): readonly ModelEntry[] {
+  listModels(): readonly ModelEntry[] {
     return this.models;
   }
 
-  defaultFor(role: RunRole): string | undefined {
-    return this.defaults.get(role);
+  listRoles(): readonly RoleEntry[] {
+    return [...this.roles.values()];
   }
 
-  /** Resolve a model id, falling back to the role default, then the first enabled. */
-  resolve(requested: string | undefined, role: RunRole): string {
-    if (requested !== undefined && this.models.some((m) => m.id === requested)) {
-      return requested;
+  role(id: string): RoleEntry | undefined {
+    return this.roles.get(id);
   }
-    const d = this.defaultFor(role);
-    if (d !== undefined) return d;
+
+  /**
+   * Resolve a model id for a run. Priority: teacher's explicit request → the
+   * role preset's default → the first admin-enabled model. `roleId` is a string
+   * so unknown roles degrade gracefully to the fallback rather than throwing.
+   */
+  resolve(requestedModel: string | undefined, roleId: string): string {
+    if (requestedModel !== undefined && this.models.some((m) => m.id === requestedModel)) {
+      return requestedModel;
+    }
+    const role = this.roles.get(roleId);
+    if (role?.defaultModel !== undefined) return role.defaultModel;
     const first = this.models[0];
     if (first === undefined) throw new Error("no models enabled for this Hub");
     return first.id;

hub/src/agent/runner.ts

@@ -11,7 +11,6 @@
  */
 import type { AgentProvider, ChatResponse, Message, ToolCallPart } from "./provider.js";
 import type { ToolContext, ToolRegistry } from "./tools.js";
-import type { RunRole } from "./models.js";
 
 /** What the runner needs about the project to seed and bound a run. */
 export interface ProjectContext {
@@ -26,7 +25,6 @@ export interface RunRequest {
   readonly prompt: string;
   /** Resolved model id (already chosen by the caller per ADR-0017). */
   readonly model: string;
-  readonly role: RunRole;
   readonly project: ProjectContext;
   readonly systemPrompt?: string;
   /** Iteration cap before the run is returned as `length`. Default 25. */

hub/src/server.ts

@@ -24,7 +24,11 @@ function main(): void {
       { id: "z-ai/glm-4.6", label: "GLM-4.6", toolCapable: true },
       { id: "anthropic/claude-3.5-sonnet", label: "Claude 3.5 Sonnet", toolCapable: true },
     ],
-    { draft: "z-ai/glm-4.6", review: "anthropic/claude-3.5-sonnet" },
+    [
+      // Roles are data here — admin/teachers add presets, not code changes.
+      { id: "draft", label: "草稿", defaultModel: "z-ai/glm-4.6" },
+      { id: "review", label: "审校", defaultModel: "anthropic/claude-3.5-sonnet" },
+    ],
   );
 
   const tools = new ToolRegistry();
@@ -36,11 +40,9 @@ function main(): void {
   );
 
   const model = models.resolve(undefined, "draft");
-
   runAgent(provider, tools, {
     prompt: "ping",
     model,
-    role: "draft",
     project: {
       projectId: "proj-skeleton",
       boundChatId: "chat-skeleton",