feat: plan 18

packages/casan-control-panel/backend/src/chat/chat.controller.ts

@@ -1,4 +1,5 @@
-import { Body, Controller, Get, Headers, Inject, Post, Query } from '@nestjs/common';
+import { Body, Controller, Get, Headers, Inject, Post, Query, Res } from '@nestjs/common';
+import type { Response } from 'express';
 import { ok } from '../common/api-response.js';
 import { actorFromHeaders } from '../common/auth-context.js';
 import { ChatAskInput, ChatService } from './chat.service.js';
@@ -12,6 +13,15 @@ export class ChatController {
     return ok(this.svc.ask(body, actorFromHeaders(headers)));
   }
 
+  @Post('ask/stream')
+  askStream(
+    @Headers() headers: Record<string, string | string[] | undefined>,
+    @Body() body: ChatAskInput,
+    @Res() res: Response,
+  ) {
+    this.svc.streamAsk(body, actorFromHeaders(headers), res);
+  }
+
   @Get('audit/verify')
   verifyAudit() {
     return ok(this.svc.verifyAudit());

packages/casan-control-panel/backend/src/chat/chat.service.ts

@@ -1,6 +1,7 @@
 import { ForbiddenException, Injectable, InternalServerErrorException } from '@nestjs/common';
-import { execFileSync } from 'node:child_process';
+import { execFileSync, spawn } from 'node:child_process';
 import { join } from 'node:path';
+import type { Response } from 'express';
 import { APP_ROOT } from '../common/app-root.js';
 import type { SettingsActor } from '../settings/settings.service.js';
 
@@ -94,6 +95,49 @@ export class ChatService {
     return { ok: res.status === 0, output: res.stdout || res.stderr };
   }
 
+  /**
+   * Item 3: streaming read-only/analysis turns. The harness emits two NDJSON
+   * phases — an UNCERTIFIED deterministic draft, then the certified final. We
+   * only wrap the harness; RBAC/H4/router verdicts remain harness-owned. The
+   * spawn is read-only (no side effect), so it is safe to stream the draft.
+   */
+  streamAsk(input: ChatAskInput, actor: SettingsActor, res: Response) {
+    if (!input.message || !input.message.trim()) {
+      throw new ForbiddenException('CHAT_DENY message required');
+    }
+    this.requireRead(actor);
+    const args = [
+      CHAT_CLI,
+      'ask',
+      '--stream',
+      '--message',
+      input.message,
+      '--actor',
+      actor.actor,
+      '--role',
+      actor.role,
+      '--project',
+      actor.project,
+      '--chat-id',
+      input.chatId || 'chat-default',
+      '--tenant',
+      actor.tenant,
+    ];
+    if (input.agentId) args.push('--agent', input.agentId);
+    if (input.skillId) args.push('--skill', input.skillId);
+    if (input.delegationLevel !== undefined) args.push('--delegation-level', String(input.delegationLevel));
+    res.setHeader('Content-Type', 'application/x-ndjson; charset=utf-8');
+    res.setHeader('Cache-Control', 'no-cache');
+    res.setHeader('X-Accel-Buffering', 'no');
+    const child = spawn('python3', args, { cwd: APP_ROOT, env: { ...process.env } });
+    child.stdout.on('data', (chunk) => res.write(chunk));
+    child.on('error', () => {
+      if (!res.headersSent) res.status(500);
+      res.end();
+    });
+    child.on('close', () => res.end());
+  }
+
   replay(chatId = '', turnId = '', tenant = '') {
     const args = ['replay'];
     if (chatId) args.push('--chat-id', chatId);