feat(groups): configure message language per group instead of per route

Route.lang is removed; Group.lang now drives the message language for
every route in the group (default en, custom via KV i18n:<lang>).
dispatch.ts loads translations per group and falls back to en for
groups without a lang. Admin UI: GroupEditor gains the language field,
RouteEditor/RouteCard drop theirs; docs and config example updated.

src/__tests__/discord.test.ts

@@ -259,4 +259,62 @@ describe("dispatchEvent fallback routing", () => {
     expect(sent.filter((u) => u.includes("/222/"))).toHaveLength(1);
     expect(sent.filter((u) => u.includes("/111/"))).toHaveLength(0);
   });
+
+  it("uses the group's message language (not the route's)", async () => {
+    const bodies: string[] = [];
+    mockFetch((url, init) => {
+      bodies.push(String(init?.body ?? ""));
+      return new Response("{}", { status: 200 });
+    });
+    const kv = createMockKV();
+    await kv.put(
+      "config:groups",
+      JSON.stringify([
+        { id: "zh-group", name: "中文组", adminIds: [], lang: "zh" },
+        { id: "en-group", name: "English", adminIds: [] },
+      ]),
+    );
+    const env = createEnv({ KV: kv, DB: createMockDB() });
+    const routes: Route[] = [
+      {
+        id: "zh-push",
+        name: "ZH",
+        enabled: true,
+        groupId: "zh-group",
+        filters: [{ type: "event", match: "push" }],
+        targets: [{ channelId: "111" }],
+      },
+      {
+        id: "en-push",
+        name: "EN",
+        enabled: true,
+        groupId: "en-group",
+        filters: [{ type: "event", match: "push" }],
+        targets: [{ channelId: "222" }],
+      },
+    ];
+
+    await dispatchEvent(
+      { ...baseConfig, routes },
+      {
+        event: "push",
+        payload: {
+          repository: { full_name: "owner/repo" },
+          commits: [{ id: "abc", message: "fix", author: { name: "a" } }],
+          ref: "refs/heads/main",
+          compare: "https://example.com/compare",
+        },
+      },
+      env,
+    );
+
+    expect(bodies).toHaveLength(2);
+    const titles = bodies.map((b) => {
+      const parsed = JSON.parse(b) as { embeds?: Array<{ title?: string }> };
+      return parsed.embeds?.[0]?.title ?? "";
+    });
+    expect(titles.sort()).toEqual(
+      ["owner/repo: 推送了 1 个提交", "owner/repo: Pushed 1 commit"].sort(),
+    );
+  });
 });

src/core/dispatch.ts

@@ -9,7 +9,11 @@ import { getDriver } from "../drivers";
 import type { SendResult } from "../drivers/types";
 
 export async function dispatchEvent(config: Config, event: WebhookEvent, env: Env): Promise<void> {
-  const langs = [...new Set(config.routes.map((r) => r.lang ?? "en"))];
+  const groups = await loadGroups(env.KV);
+  const groupById = new Map(groups.map((g) => [g.id, g]));
+
+  // Message language is configured per group (Group.lang), not per route.
+  const langs = [...new Set(groups.map((g) => g.lang ?? "en"))];
   const trMap = new Map<string, Translations>();
   await Promise.all(
     langs.map(async (lang) => {
@@ -17,8 +21,6 @@ export async function dispatchEvent(config: Config, event: WebhookEvent, env: En
     }),
   );
 
-  const groups = await loadGroups(env.KV);
-  const groupById = new Map(groups.map((g) => [g.id, g]));
   const owners = eventOwners(event);
 
   const accepted = (route: Route): boolean => {
@@ -53,8 +55,8 @@ export async function dispatchEvent(config: Config, event: WebhookEvent, env: En
     const targets = route.targets && route.targets.length > 0 ? route.targets : [];
     if (targets.length === 0) return;
 
-    const tr = trMap.get(route.lang ?? "en")!;
     const group = route.groupId ? groupById.get(route.groupId) : undefined;
+    const tr = trMap.get(group?.lang ?? "en")!;
     const showEmoji = group?.emoji !== false;
     const message = formatEvent(route, event, tr, showEmoji);
     if (route.discordRoleIds?.length) {

src/types.ts

@@ -58,7 +58,6 @@ export interface Route {
   enabled: boolean;
   filters: Filter[];
   targets: RouteTarget[];
-  lang?: string;
   groupId?: string;
   /**
    * Fallback route: only fires when no other (non-fallback) route matched the
@@ -120,6 +119,11 @@ export interface Group {
    * Defaults to true when omitted.
    */
   emoji?: boolean;
+  /**
+   * Message language for every route in this group (e.g. "en", "zh"; custom
+   * via KV i18n:<lang>). Defaults to "en" when omitted.
+   */
+  lang?: string;
 }
 
 export interface Filter {

src/web/admin-routes.ts

@@ -87,9 +87,6 @@ function validateRoutes(
     }
     if (typeof r.enabled !== "boolean")
       return { ok: false, error: `route "${r.id}".enabled must be boolean` };
-    if (r.lang !== undefined && typeof r.lang !== "string") {
-      return { ok: false, error: `route "${r.id}".lang must be a string` };
-    }
     if (r.fallback !== undefined && typeof r.fallback !== "boolean") {
       return { ok: false, error: `route "${r.id}".fallback must be a boolean` };
     }
@@ -283,6 +280,9 @@ function validateGroups(
     if (g.emoji !== undefined && typeof g.emoji !== "boolean") {
       return { ok: false, error: `group "${g.id}".emoji must be a boolean` };
     }
+    if (g.lang !== undefined && typeof g.lang !== "string") {
+      return { ok: false, error: `group "${g.id}".lang must be a string` };
+    }
   }
   return { ok: true, groups: groups as Group[] };
 }