feat: add model selector dropdown to UI

refactor: type server route request models with DesignState/DesignPlan

refactor: update BaseOrchestrator and MockChatBackend to return ChatTurnResponse

fix: ask agent confirm now correctly updates plan card fields

fix: path traversal in model endpoints, XSS in plan card, remove dead code

feat: add 3MF export and /api/models/{name}.3mf endpoint

feat: add /api/plan/approve and /api/plan/reject endpoints

refactor: eliminate all Serializer classes, use Pydantic model_dump() directly

refactor: typed Pydantic config + Pydantic result models, eliminate dict access

refactor: remove SingleCallOrchestrator, unify all backends through CrewAI

feat(api): add GET /api/models/{name}.gcode endpoint

fix: surface CAD execution errors to user instead of silently failing

feat: remove mock/claude backends, default to gemini, add openai toggle

refactor: server uses Settings + BackendFactory, eliminate hardcoded paths and backend checks

refactor: use serializers to eliminate duplicated result building

feat: switch Gemini to CrewAI multi-call orchestrator

feat: add DesignState memory + localStorage persistence

fix: address agentic review — security, prompts, retry, validation

feat: add chat API, MCP chat_turn tool, and rewrite frontend

refactor: reorganize codebase into core/, server/, agents/ packages