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_backend/app/automations/schemas/definition/__init__.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from .envelope import AutomationDefinition
+from .envelope import AutomationDefinition, AutomationModels
 from .execution import Execution
 from .inputs import Inputs
 from .metadata import Metadata
@@ -11,6 +11,7 @@ from .trigger_spec import TriggerSpec
 
 __all__ = [
     "AutomationDefinition",
+    "AutomationModels",
     "Execution",
     "Inputs",
     "Metadata",

surfsense_backend/app/automations/schemas/definition/envelope.py

@@ -11,6 +11,21 @@ from .plan_step import PlanStep
 from .trigger_spec import TriggerSpec
 
 
+class AutomationModels(BaseModel):
+    """Captured model profile for an automation.
+
+    Snapshotted from the search space's preferences at create time so runs are
+    insulated from later chat/search-space model changes. Config-id conventions
+    match the shared scheme (``0`` Auto, ``< 0`` global, ``> 0`` BYOK).
+    """
+
+    model_config = ConfigDict(extra="forbid")
+
+    agent_llm_id: int = 0
+    image_generation_config_id: int = 0
+    vision_llm_config_id: int = 0
+
+
 class AutomationDefinition(BaseModel):
     """Top-level shape of an automation."""
 
@@ -24,3 +39,7 @@ class AutomationDefinition(BaseModel):
     plan: list[PlanStep] = Field(..., min_length=1)
     execution: Execution = Field(default_factory=Execution)
     metadata: Metadata = Field(default_factory=Metadata)
+    # Captured server-side at create() and preserved across update(); resolved
+    # at runtime instead of the live search space. Optional so drafts/builder
+    # payloads validate without it.
+    models: AutomationModels | None = None