fix(resolveGgmlTypeOption): accept case-insensitive ggml type names

[andreinknv]

Summary

resolveGgmlTypeOption("q8_0") currently returns undefined. The lookup uses Object.hasOwn(GgmlType, option) against the uppercase-by-convention enum keys (Q8_0, F16, BF16, …), so any lowercase/mixed-case input falls through unrecognized. The caller then quietly defaults to F16 with no warning — a silent, hard-to-debug "why is my Q8 KV cache behaving like FP16?" failure.

This PR uppercases the string input before the lookup. Numeric GgmlType values still resolve unchanged. Invalid strings still return undefined.

Why

Two callsites that consume this string:

1. LlamaContextOptions.experimentalKvCacheKeyType / experimentalKvCacheValueType — operators set these from config files, where lowercase quant identifiers (q8_0, q4_0, bf16) are common because GGUF filenames carry them in that case (e.g. qwen2.5-coder-7b-instruct-q4_k_m.gguf).

2. CLI flags --kv-cache-key-type / --kv-cache-value-type — same expectation; users mirror the lowercase GGUF naming.

Reproduction (matches what surfaced while benchmarking a quantized-KV configuration): pass "q8_0" to experimentalKvCacheKeyType, run a context, observe VRAM/perf numbers that match the F16 baseline instead of Q8. No error is raised — the silent fallback makes it look like the override is working when it isn't.

After

resolveGgmlTypeOption("q8_0")  // => GgmlType.Q8_0  (was: undefined)
resolveGgmlTypeOption("Q8_0")  // => GgmlType.Q8_0  (unchanged)
resolveGgmlTypeOption("bf16")  // => GgmlType.BF16  (was: undefined)
resolveGgmlTypeOption("nope")  // => undefined      (unchanged)
resolveGgmlTypeOption(undefined)  // => undefined  (unchanged)
resolveGgmlTypeOption(13 /* GgmlType.Q8_0 */)  // => GgmlType.Q8_0 (unchanged)

Compatibility

• Strings that already worked still work (uppercased-first is idempotent for already-upper input).
• Strings that previously returned undefined now resolve when their uppercase form is a valid key. This is a strict superset of the prior accepted-input set — no caller that depended on undefined for those inputs should exist (the API contract is "valid → enum value, invalid → undefined").
• No public-API breakage.

Test plan

• Manual: resolveGgmlTypeOption("q8_0") now returns GgmlType.Q8_0; "Q8_0" still does.
• Manual: invalid strings ("nope", "") still return undefined.
• CI on this PR.

🤖 Generated with Claude Code