feat: improve Feishu markdown rendering and processing status feedback

- Add buildOutboundPayload: detect markdown format, isolate code blocks,
  force plain text for tables, fallback from post to text on API rejection
- Add addReaction/removeReaction for processing status lifecycle
- Replace THUMBSUP with Typing→(remove on success | CrossMark on failure)
- Add unit tests for markdown rendering (15) and reactions (6)

hub/src/feishu/trigger.ts

@@ -11,7 +11,7 @@
 import type { Prisma, PrismaClient } from "@prisma/client";
 import { z } from "zod";
 import type { FastifyBaseLogger } from "fastify";
-import { sendText, sendTextMessage, patchTextMessage, reactToMessage, downloadMessageFile, type FeishuRuntime, type MessageReceiveEvent } from "./client.js";
+import { sendText, sendTextMessage, patchTextMessage, reactToMessage, addReaction, removeReaction, downloadMessageFile, type FeishuRuntime, type MessageReceiveEvent } from "./client.js";
 import { runAgent as defaultRunAgent, type ProjectContext, type RunRequest, type RunResult } from "../agent/runner.js";
 import type { RuntimeSettings } from "../settings/runtime.js";
 import { acquireLock, currentLockRunId, releaseLock } from "../lock.js";
@@ -309,8 +309,11 @@ export function makeTriggerHandler(deps: TriggerDeps) {
       workspaceDir: project.workspaceDir,
     };
 
-    // Emoji reaction on the user's message (acknowledge receipt).
-    await reactToMessage(rt, msg.message_id, "THUMBSUP");
+    const processingReactionId = await addReaction(rt, msg.message_id, "Typing");
+    const removeProcessingReaction = async (): Promise<boolean> => {
+      if (processingReactionId === null) return false;
+      return removeReaction(rt, msg.message_id, processingReactionId);
+    };
 
     // Stream agent response as text-as-card messages. Lazy-init: don't send
     // anything until the first text-delta arrives (avoids empty placeholder).
@@ -381,8 +384,13 @@ export function makeTriggerHandler(deps: TriggerDeps) {
           action: "run.finished",
           metadata: { status: result.status, deliveredFiles },
         });
+        await removeProcessingReaction();
       })
       .catch(async (e) => {
+        const removedProcessingReaction = await removeProcessingReaction();
+        if (removedProcessingReaction) {
+          await addReaction(rt, msg.message_id, "CrossMark");
+        }
         try {
           await deps.prisma.agentRun.update({
             where: { id: run.id },