feat: gateway CRUD routes — conversations, projects, missions, tasks (P1-005/006) (#72)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/gateway/src/conversations/conversations.controller.ts

@@ -0,0 +1,83 @@
+import {
+  Body,
+  Controller,
+  Delete,
+  Get,
+  HttpCode,
+  HttpStatus,
+  Inject,
+  NotFoundException,
+  Param,
+  Patch,
+  Post,
+  UseGuards,
+} from '@nestjs/common';
+import type { Brain } from '@mosaic/brain';
+import { BRAIN } from '../brain/brain.module.js';
+import { AuthGuard } from '../auth/auth.guard.js';
+import { CurrentUser } from '../auth/current-user.decorator.js';
+import type {
+  CreateConversationDto,
+  UpdateConversationDto,
+  SendMessageDto,
+} from './conversations.dto.js';
+
+@Controller('api/conversations')
+@UseGuards(AuthGuard)
+export class ConversationsController {
+  constructor(@Inject(BRAIN) private readonly brain: Brain) {}
+
+  @Get()
+  async list(@CurrentUser() user: { id: string }) {
+    return this.brain.conversations.findAll(user.id);
+  }
+
+  @Get(':id')
+  async findOne(@Param('id') id: string) {
+    const conversation = await this.brain.conversations.findById(id);
+    if (!conversation) throw new NotFoundException('Conversation not found');
+    return conversation;
+  }
+
+  @Post()
+  async create(@CurrentUser() user: { id: string }, @Body() dto: CreateConversationDto) {
+    return this.brain.conversations.create({
+      userId: user.id,
+      title: dto.title,
+      projectId: dto.projectId,
+    });
+  }
+
+  @Patch(':id')
+  async update(@Param('id') id: string, @Body() dto: UpdateConversationDto) {
+    const conversation = await this.brain.conversations.update(id, dto);
+    if (!conversation) throw new NotFoundException('Conversation not found');
+    return conversation;
+  }
+
+  @Delete(':id')
+  @HttpCode(HttpStatus.NO_CONTENT)
+  async remove(@Param('id') id: string) {
+    const deleted = await this.brain.conversations.remove(id);
+    if (!deleted) throw new NotFoundException('Conversation not found');
+  }
+
+  @Get(':id/messages')
+  async listMessages(@Param('id') id: string) {
+    const conversation = await this.brain.conversations.findById(id);
+    if (!conversation) throw new NotFoundException('Conversation not found');
+    return this.brain.conversations.findMessages(id);
+  }
+
+  @Post(':id/messages')
+  async addMessage(@Param('id') id: string, @Body() dto: SendMessageDto) {
+    const conversation = await this.brain.conversations.findById(id);
+    if (!conversation) throw new NotFoundException('Conversation not found');
+    return this.brain.conversations.addMessage({
+      conversationId: id,
+      role: dto.role,
+      content: dto.content,
+      metadata: dto.metadata,
+    });
+  }
+}