feat: add default models for agents

[ekim1707]

Description

Facilitate default models being assigned to agents. This PR requires a corresponding PR from elsa-beta for full implementation.

Changes Made

new-room-page.tsx — Calls getWorkspace and sets the agent's default model if configured. Restores user's default model if agent is unselected.

types.d.ts — Added config_json?: { model_id?: string } to the Workspace interface. This exposes the backend-returned
field that holds the default model engine ID for a workspace, which is used to hydrate the dropdown when opening the
edit form or agent detail page.

chat.store.ts — Added the modelId?: string | null parameter to editWorkspace and updated the pixel string to
conditionally include modelId in the call. When modelId is null it sends modelId="" to clear it on the backend; when
undefined (not passed at all) it omits modelId entirely to leave it unchanged.

How to Test

1. Run elsa-beta dev server (use this branch: https://github.com/elsa-chat/elsa-beta/tree/673-default-model-for-agents-v2)
2. Run semoss-ui dev server (673-default-model-for-agents)
3. Navigate to the Agents section in the semoss-ui shell — it loads elsa-beta in the iframe

Then test:

• Create agent — verify the Default Model dropdown appears between Description and the tabs
• Edit agent — verify the dropdown shows the saved model and can be changed or cleared
• Agent detail page — verify the "Default model" badge always shows (either the model name or "No default model")
• New room page — verify the model showing in the dropdown matches the agent's default model (or lack thereof). strip away the agent and make sure the default model displays accurately as well.

[snyk-io]

✅ Snyk checks have passed. No issues have been found so far.

Status	Scan Engine	Critical	High	Medium	Low	Total (0)
✅	Open Source Security	0	0	0	0	0 issues

💻 Catch issues earlier using the plugins for VS Code, JetBrains IDEs, Visual Studio, and Eclipse.