nextbit: add pricing to all models, add alia-salamandra:40b and unslopnemo:12b

[Copilot]

All nextbit provider models were missing [cost] entries. Two models (alia-salamandra:40b, unslopnemo:12b) were also absent entirely.

Pricing added

Model	Input	Output
alia-salamandra:40b	$0.30	$0.60
deepseek:qwen3-r1-32b	$0.29	$0.29
euryale:33-70b	$0.65	$0.75
gemma-2:27b-it	$0.65	$0.65
gemma4:26b-a4b	$0.15	$0.40
gpt-oss:20b	$0.10	$0.45
microsoft:phi-4	$0.07	$0.14
ministral:3-14b	$0.35	$0.35
ministral:3b	$0.15	$0.15
ministral:8b-2512	$0.30	$0.30
mythomax:13b	$0.06	$0.06
qwen3:14b	$0.10	$0.24
qwen3:30b	$0.14	$0.55
qwen:3.5-35b	$0.30	$1.80
remm-slerp:l2-13b	$0.45	$0.65
rocinante:12b	$0.17	$0.43
unslopnemo:12b	$0.40	$0.40

Structural fixes

• Removed omit = ["cost"] from extending models that now define their own [cost] block (deepseek:qwen3-r1-32b, microsoft:phi-4, ministral:3b, qwen3:14b, qwen:3.5-35b)
• Created alia-salamandra:40b.toml and unslopnemo:12b.toml as new standalone model definitions (32K/32K context)