feat(dllm): backend packaging, gallery index, CI matrix

Registers the dllm backend across every surface: backend gallery index
(cpu amd64+arm64 with manifest merge, cuda13, l4t-cuda13 for GB10-class
hardware; no darwin per engine scope), top-level Makefile targets,
bump_deps pin tracking for DLLM_VERSION, and the curated known-backends
list for /backends/known (pref-only: auto-detecting on .gguf would
shadow llama-cpp). Note: image builds and the nightly bump leg stay red
until github.com/mudler/dllm.cpp is published (planned at merge time).

Assisted-by: Claude Code (Fable 5)
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

backend/go/dllm/Makefile

@@ -14,6 +14,10 @@
 # That's what the gated C-ABI binding smoke uses (DLLM_TEST_LIBRARY). The
 # default target below does the proper clone-at-pin + cmake build so CI
 # doesn't need a side-checkout.
+#
+# NOTE: github.com/mudler/dllm.cpp is still private (publishing is planned);
+# until then the anonymous clone below fails. Use the symlink shortcut above
+# with a local checkout, or a git credential helper with access to the repo.
 
 DLLM_VERSION?=b22fcebebfb225131113188599a9ae542b2935d7
 DLLM_REPO?=https://github.com/mudler/dllm.cpp

backend/go/dllm/dllm.go

@@ -275,8 +275,8 @@ func (d *Dllm) requestOptsJSON(opts *pb.PredictOptions) (string, error) {
 		// The engine rounds n_predict UP to a whole number of diffusion
 		// blocks (the canvas is denoised block-wise), so the completion may
 		// run slightly past the requested budget. Tokens==0 omits the key so
-		// the engine's GGUF-metadata default applies (the C-ABI documents
-		// per-key defaults; no hardcoded 256 like ds4's grpc-server).
+		// the C-ABI default of 256 applies (hardcoded in capi.cpp's
+		// parse_gen_opts, independent of canvas_length).
 		m["n_predict"] = n
 	}
 	if s := opts.GetSeed(); s > 0 {

backend/index.yaml

@@ -95,6 +95,29 @@
     nvidia-l4t-cuda-13: "cuda13-nvidia-l4t-arm64-ds4"
     metal: "metal-ds4"
     metal-darwin-arm64: "metal-ds4"
+- &dllm
+  name: "dllm"
+  alias: "dllm"
+  license: mit
+  description: |
+    mudler/dllm.cpp - DiffusionGemma block-diffusion LLM inference engine
+    (C++/ggml, GGUF weights). Decodes whole token canvases per diffusion
+    round instead of autoregressive sampling. Runs on CPU and NVIDIA CUDA 13
+    (including Jetson/GB10 L4T targets).
+  urls:
+    - https://github.com/mudler/dllm.cpp
+  tags:
+    - text-to-text
+    - LLM
+    - gguf
+    - diffusion
+    - CPU
+    - CUDA
+  capabilities:
+    default: "cpu-dllm"
+    nvidia: "cuda13-dllm"
+    nvidia-cuda-13: "cuda13-dllm"
+    nvidia-l4t-cuda-13: "cuda13-nvidia-l4t-arm64-dllm"
 - &whispercpp
   name: "whisper"
   alias: "whisper"
@@ -1272,6 +1295,13 @@
     nvidia-l4t-cuda-13: "cuda13-nvidia-l4t-arm64-ds4-development"
     metal: "metal-ds4-development"
     metal-darwin-arm64: "metal-ds4-development"
+- !!merge <<: *dllm
+  name: "dllm-development"
+  capabilities:
+    default: "cpu-dllm-development"
+    nvidia: "cuda13-dllm-development"
+    nvidia-cuda-13: "cuda13-dllm-development"
+    nvidia-l4t-cuda-13: "cuda13-nvidia-l4t-arm64-dllm-development"
 - !!merge <<: *stablediffusionggml
   name: "stablediffusion-ggml-development"
   capabilities:
@@ -1859,6 +1889,37 @@
   uri: "quay.io/go-skynet/local-ai-backends:master-metal-darwin-arm64-ds4"
   mirrors:
     - localai/localai-backends:master-metal-darwin-arm64-ds4
+## dllm
+- !!merge <<: *dllm
+  name: "cpu-dllm"
+  uri: "quay.io/go-skynet/local-ai-backends:latest-cpu-dllm"
+  mirrors:
+    - localai/localai-backends:latest-cpu-dllm
+- !!merge <<: *dllm
+  name: "cpu-dllm-development"
+  uri: "quay.io/go-skynet/local-ai-backends:master-cpu-dllm"
+  mirrors:
+    - localai/localai-backends:master-cpu-dllm
+- !!merge <<: *dllm
+  name: "cuda13-dllm"
+  uri: "quay.io/go-skynet/local-ai-backends:latest-gpu-nvidia-cuda-13-dllm"
+  mirrors:
+    - localai/localai-backends:latest-gpu-nvidia-cuda-13-dllm
+- !!merge <<: *dllm
+  name: "cuda13-dllm-development"
+  uri: "quay.io/go-skynet/local-ai-backends:master-gpu-nvidia-cuda-13-dllm"
+  mirrors:
+    - localai/localai-backends:master-gpu-nvidia-cuda-13-dllm
+- !!merge <<: *dllm
+  name: "cuda13-nvidia-l4t-arm64-dllm"
+  uri: "quay.io/go-skynet/local-ai-backends:latest-nvidia-l4t-cuda-13-arm64-dllm"
+  mirrors:
+    - localai/localai-backends:latest-nvidia-l4t-cuda-13-arm64-dllm
+- !!merge <<: *dllm
+  name: "cuda13-nvidia-l4t-arm64-dllm-development"
+  uri: "quay.io/go-skynet/local-ai-backends:master-nvidia-l4t-cuda-13-arm64-dllm"
+  mirrors:
+    - localai/localai-backends:master-nvidia-l4t-cuda-13-arm64-dllm
 ## whisper
 - !!merge <<: *whispercpp
   name: "whisper-development"