fix(security): enforce registered endpoint authority

Require caller-supplied model endpoints to resolve through enabled owner-visible registrations, harden session path encoding, and remove the SVG title HTML parsing sink.

routes/task/task_routes.py

@@ -14,6 +14,7 @@ from core.database import SessionLocal, ScheduledTask, TaskRun, NotificationLog
 from core.constants import internal_api_base
 from src.auth_helpers import get_current_user
 from src.constants import DATA_DIR, EMAIL_URGENCY_CACHE_DIR
+from src.endpoint_resolver import resolve_owner_registered_endpoint_url
 from src.task_action_policy import (
     ADMIN_ONLY_TASK_ACTIONS,
     is_admin_only_task_action,
@@ -519,6 +520,12 @@ def setup_task_routes(task_scheduler) -> APIRouter:
         db = SessionLocal()
         try:
             then_task_id = _validate_then_task_id(db, req.then_task_id, user)
+            endpoint_url = None
+            if req.endpoint_url:
+                try:
+                    endpoint_url = resolve_owner_registered_endpoint_url(db, req.endpoint_url, user)
+                except ValueError as exc:
+                    raise HTTPException(400, str(exc)) from exc
             notifications_enabled = (
                 False if req.task_type == "action" and req.notifications_enabled is None
                 else bool(req.notifications_enabled) if req.notifications_enabled is not None
@@ -555,7 +562,7 @@ def setup_task_routes(task_scheduler) -> APIRouter:
                 status="active" if (req.trigger_type in ("event", "webhook") or next_run) else "completed",
                 output_target=req.output_target,
                 model=req.model or None,
-                endpoint_url=req.endpoint_url or None,
+                endpoint_url=endpoint_url,
                 then_task_id=then_task_id,
                 webhook_token=webhook_token,
                 notifications_enabled=notifications_enabled,
@@ -755,7 +762,14 @@ def setup_task_routes(task_scheduler) -> APIRouter:
             if req.model is not None:
                 task.model = req.model or None
             if req.endpoint_url is not None:
-                task.endpoint_url = req.endpoint_url or None
+                try:
+                    # An empty override restores the existing default-model workflow.
+                    task.endpoint_url = (
+                        resolve_owner_registered_endpoint_url(db, req.endpoint_url, user)
+                        if req.endpoint_url else None
+                    )
+                except ValueError as exc:
+                    raise HTTPException(400, str(exc)) from exc
             if req.trigger_type is not None:
                 # Generate webhook token when switching to webhook trigger
                 if req.trigger_type == "webhook" and not task.webhook_token: