Restrict asset state store access to registered tasks

[fat-catTW]

Why:

Asset state store entries are scoped to assets, but execution API task tokens should not be able to access every active asset.

Previously, any task with a valid execution token could read or mutate state for unrelated assets. This made asset state store access broader than the task's declared asset relationships.

Solution:

Restrict the execution API asset state store routes so task tokens can only access assets registered to that task as an inlet or outlet.

The routes now check TaskInletAssetReference and TaskOutletAssetReference before allowing GET, PUT, DELETE, or CLEAR operations. Unregistered task access returns 403 Forbidden.

Watcher writes keep using the existing non-task path because watcher tokens are not backed by task instances.

Tests cover forbidden access for unregistered tasks and allowed access for inlet/outlet-registered tasks.

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