v0.40.0-rc0: llama-server: prepare to remove compatibility patch

Add manifest-list storage so runner-specific manifests can coexist under one tag while preserving existing v1 tags as best-effort downgrade anchors. Show/list/copy/remove/pull/push now understand runner and digest selection and transfer referenced child manifests and layers.

Add lazy local compatibility migration for legacy Ollama GGUFs into llama.cpp-compatible children, covering the patched model families and preserving parser/renderer, templates, projectors, media metadata, split GGUFs, and MTP/draft tensors where applicable.

Extend create/import/conversion paths for the same compatibility rules, harden manifest-list combine validation, and add focused manifest, migration, transfer, and integration coverage for first-load conversion plus chat/tools/vision/audio/embedding behavior.