🦺 Add connection validation and safeguards to claw

This makes it so that connect_raw in claw does not re-connect a shmpath that was already connected to a given sfid and will also call a disconnect for an sfid if a shmpath is already associated to it and we try to connect a different shmpath.

This will prevent bugs like the nvenc quiddity segfaulting when two connections are made without a call to disconnect and will prevent behaviours like stutters in video streams when calling try_connect multiple times with the same source.

Resolves #170 (closed)