Resolve llama.cpp model details when request aliases differ from catalog IDs

• Status: Todo
• Kind: Bug
• Authors: jp
• Date: 2026-08-21
• Label: domain=llm
• Label: llm-provider=llamacpp
• Label: package=jp_llm
• Label: type=bug

The llama.cpp fixture requests llamacpp/qwen3.5:9b, while /v1/models reports unsloth/Qwen3.5-9B-GGUF. map_model strips the vendor prefix to Qwen3.5-9B-GGUF, so model_details("qwen3.5:9b") misses the loaded model and returns empty details. The accepted snapshot loses the /props context window of 8192.

The chat cassettes are also inconsistent with model discovery: chat responses identify a 35B model while /v1/models identifies a 9B model.

Acceptance criteria:

• Define and implement model identity matching for llama.cpp request aliases and loaded catalog IDs.
• Preserve the served context window when the configured request name differs from the server model ID.
• Avoid ambiguous fallback when a server exposes more than one model.
• Re-record a self-consistent llama.cpp fixture corpus using one loaded model.
• Make the model-details fixture assert the expected ID and context window instead of accepting empty details.