fix: Switch auto-spawn from discuss to refine agent, surface in UI

The auto-spawned agent on initiative creation was using discuss mode
(Q&A) when it should use refine mode (expand content). Now:

- Description seeds root page as tiptap content (split on double newlines)
- Spawns refine agent with the populated page in inputContext
- getActiveRefineAgent broadened to also surface discuss agents (for
  CLI-spawned discuss agents)
- RefineAgentPanel shows mode-appropriate label for discuss vs refine

apps/server/trpc/routers/initiative.ts

@@ -7,7 +7,8 @@ import { z } from 'zod';
 import type { ProcedureBuilder } from '../trpc.js';
 import { requireAgentManager, requireInitiativeRepository, requireProjectRepository, requireTaskRepository } from './_helpers.js';
 import { deriveInitiativeActivity } from './initiative-activity.js';
-import { buildDiscussPrompt } from '../../agent/prompts/index.js';
+import { buildRefinePrompt } from '../../agent/prompts/index.js';
+import type { PageForSerialization } from '../../agent/content-serializer.js';
 
 export function initiativeProcedures(publicProcedure: ProcedureBuilder) {
   return {
@@ -47,38 +48,57 @@ export function initiativeProcedures(publicProcedure: ProcedureBuilder) {
           await projectRepo.setInitiativeProjects(initiative.id, input.projectIds);
         }
 
+        // Create root page — seed with description as tiptap content if provided
+        const descriptionText = input.description?.trim();
+        let rootPage: { id: string; parentPageId: string | null; title: string; content: string | null; sortOrder: number } | null = null;
         if (ctx.pageRepository) {
-          await ctx.pageRepository.create({
+          const tiptapContent = descriptionText
+            ? JSON.stringify({
+              type: 'doc',
+              content: descriptionText.split(/\n{2,}/).map(para => ({
+                type: 'paragraph',
+                content: [{ type: 'text', text: para.trim() }],
+              })).filter(p => p.content[0].text),
+            })
+            : null;
+
+          rootPage = await ctx.pageRepository.create({
             initiativeId: initiative.id,
             parentPageId: null,
             title: input.name,
-            content: null,
+            content: tiptapContent,
             sortOrder: 0,
           });
         }
 
-        // Auto-spawn discuss agent when description is provided
-        if (input.description?.trim() && ctx.agentManager && ctx.taskRepository) {
+        // Auto-spawn refine agent when description is provided
+        if (descriptionText && rootPage && ctx.agentManager && ctx.taskRepository) {
           try {
             const taskRepo = requireTaskRepository(ctx);
             const agentManager = requireAgentManager(ctx);
 
             const task = await taskRepo.create({
               initiativeId: initiative.id,
-              name: `Discuss: ${initiative.name}`,
-              description: input.description.trim(),
-              category: 'discuss',
+              name: `Refine: ${initiative.name}`,
+              description: descriptionText,
+              category: 'refine',
               status: 'in_progress',
             });
 
-            const prompt = buildDiscussPrompt();
+            const pages: PageForSerialization[] = [{
+              id: rootPage.id,
+              parentPageId: null,
+              title: rootPage.title,
+              content: rootPage.content,
+              sortOrder: 0,
+            }];
 
             agentManager.spawn({
               taskId: task.id,
-              prompt,
-              mode: 'discuss',
+              prompt: buildRefinePrompt(),
+              mode: 'refine',
               initiativeId: initiative.id,
-              inputContext: { initiative, task },
+              inputContext: { initiative, pages },
             });
           } catch {
             // Fire-and-forget — don't fail initiative creation if agent spawn fails