feat: show tool activity sub-lines in progress messages

Display subagent tool descriptions as sub-lines under the main
progress text, updating in-place via Discord message edit.
Shows up to 5 recent tool activities (e.g., "Reading index.ts").

src/agent-runner.ts

@@ -41,7 +41,7 @@ export interface AgentInput {
 export interface AgentOutput {
   status: 'success' | 'error';
   result: string | null;
-  phase?: 'progress' | 'final';
+  phase?: 'progress' | 'final' | 'tool-activity';
   newSessionId?: string;
   error?: string;
 }
@@ -238,7 +238,11 @@ export async function runAgentProcess(
       const lines = chunk.trim().split('\n');
       for (const line of lines) {
         if (!line) continue;
-        if (line.includes('Turn in progress') || line.includes('Subagent') || line.includes('Intermediate assistant')) {
+        if (
+          line.includes('Turn in progress') ||
+          line.includes('Subagent') ||
+          line.includes('Intermediate assistant')
+        ) {
           logger.info(
             { group: group.name, chatJid: input.chatJid, runId: input.runId },
             line.replace(/^\[.*?\]\s*/, ''),