feat(automations): implement model eligibility checks for automation creation

- Added model eligibility checks to ensure automations can only use billable models (premium or BYOK).
- Introduced new API endpoint to report model eligibility status for search spaces.
- Updated frontend components to display eligibility alerts and disable creation options when models are not billable.
- Enhanced automation creation forms to reflect model eligibility, preventing users from submitting invalid configurations.
- Implemented server-side logic to capture and preserve model preferences across automation edits, ensuring consistent behavior during execution.

surfsense_web/lib/apis/automations-api.service.ts

@@ -6,6 +6,7 @@ import {
 	automationCreateRequest,
 	automationListResponse,
 	automationUpdateRequest,
+	modelEligibility,
 	type RunListParams,
 	run,
 	runListResponse,
@@ -62,6 +63,13 @@ class AutomationsApiService {
 		return baseApiService.delete(`${BASE}/${automationId}`);
 	};
 
+	// Whether the search space's models are billable for automations (premium
+	// global or BYOK). Used to gate creation surfaces before submit.
+	getModelEligibility = async (searchSpaceId: number) => {
+		const qs = new URLSearchParams({ search_space_id: String(searchSpaceId) });
+		return baseApiService.get(`${BASE}/model-eligibility?${qs.toString()}`, modelEligibility);
+	};
+
 	// ---- Triggers (sub-resource) --------------------------------------------
 
 	addTrigger = async (automationId: number, request: TriggerCreateRequest) => {