feat(orchestrator): add MS23 per-agent message history and SSE stream endpoints

GET /agents/:id/messages - paginated message history
GET /agents/:id/messages/stream - SSE live stream with replay

Partial #693

apps/orchestrator/Dockerfile

@@ -47,11 +47,10 @@ COPY --from=deps /app/packages/shared/node_modules ./packages/shared/node_module
 COPY --from=deps /app/packages/config/node_modules ./packages/config/node_modules
 COPY --from=deps /app/apps/orchestrator/node_modules ./apps/orchestrator/node_modules
 
-# The repo has apps/orchestrator/prisma/schema.prisma as a symlink for CI use.
+# Overwrite the symlink (apps/orchestrator/prisma/schema.prisma → ../../api/prisma/schema.prisma)
-# Kaniko resolves destination symlinks on COPY, which fails because the symlink
+# with the real file content. Kaniko copies symlinks AS symlinks (does not follow them),
-# target (../../api/prisma/schema.prisma) doesn't exist in the container.
+# so the symlink target would be dangling inside the container. Copying the actual file
-# Fix: remove the dangling symlink first, then copy the real schema file there.
+# after the orchestrator COPY overwrites the symlink with the resolved content.
-RUN rm -f apps/orchestrator/prisma/schema.prisma
 COPY apps/api/prisma/schema.prisma ./apps/orchestrator/prisma/schema.prisma
 # pnpm turbo build runs prisma:generate (--schema=./prisma/schema.prisma) from the
 # orchestrator package context — no cross-package project-root issues.