Fix CI: config-attributes check, indexer fp32 dtype + causality
- check_config_attributes: allowlist head_dim/layer_types/mlp_bias for the DSA configs; drop the
now-unused rope_interleave field (the explicit forward always interleaves).
- Indexer: cast the weights_proj input to the layer's own dtype (it is kept in fp32 via
_keep_in_fp32_modules but tests may force-cast), fixing fp16/static-cache crashes.
- Indexer causality: select top-k only at/before each query — use the passed mask when present
(correct for padded/packed inputs), else reconstruct from position_ids (SDPA is_causal skip path).
Fixes non-causal SDPA + static-cache.