In multi-project mode the global chatManager was backed by ~/.fusion/fusion.db.
Secondary project chat sessions live in per-project DBs, so
chatManager.sendMessage() failed with 'Chat session not found' for any
project that is not the daemon's CWD.
Fix: add getOrCreateScopedChatManager to chat-project-services.ts (cached by
fusionDir, same pattern as the existing chatStore cache). POST /messages,
GET /stream, POST /cancel, and GET /sessions isGenerating enrichment all
resolve the per-project ChatManager when projectId is provided.
Fallback to global chatManager when no projectId (preserves single-project mode).
Tests: added multi-project chat routing describe block in chat-routes.test.ts.
0ce1b62809