fix(model-loader): also skip .ckpt, .zip, and .tag files when scanning models

The local model directory scan treats every non-skipped file as a model
config candidate. Sidecar artifacts that ship alongside checkpoints
(checkpoint blobs, downloaded archives, ggml-style tag files) were
slipping through and showing up as bogus models in the listing. Add
their extensions to the suffix-skip list.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-4-7 [Claude Code]