chore(gallery): add Spark Heretic JP variants

[localai-org-maint-bot]

Description

Add Spark-X2.5-4B Heretic JP for Japanese text chat, with Q4_K_M and Q8_0 llama.cpp variants. Both entries use the embedded Jinja template and an 8,192-token default context. Document installation, explicit variant selection, and the publisher's recommended output budget.

Sources: base model, Japanese adaptation and GGUF files.

Notes for Reviewers

• LocalAI's pinned llama.cpp revision bed0a856606ee4a24a164066f73d2379447033f5 includes LLM_ARCH_SPARK2_5. The entries follow the existing Spark configurations.
• Downloads are pinned to HF revision f01809e437fb3046ae9afd31d684556f9ae5dd46. Both SHA-256 values and byte sizes match the LFS API and resolve headers independently.
• Q4_K_M: 8700b9cb4be2ddf1a6b4a9230f7b9d030aeb923d0528301bc546bb5a74f21cd7 (2,600,224,384 bytes).
• Q8_0: ad25031816957ee29ff1b4c7f735f7ba785c345cd6d3f404a581110c228eb81a (4,375,021,184 bytes).
• Full-gallery YAML validation passed: 2,083 existing entries unchanged, 2,085 unique names, valid variant targets, and matching model paths. git diff --check passed.
• go test ./core/gallery -count=1 could not start: generated pkg/grpc/proto is absent. This environment also lacks make and protoc. No inference test or full weight download was performed.

Signed commits

• Yes, I signed my commits. Human DCO sign-off is required; AI sign-off is prohibited by repository policy.
• Documentation updated (docs/content/) for user-facing changes, or not applicable