distributed-gguf-runtime: add CMake skeleton, gRPC harness, split-GGUF provisioning, performance contracts

DGR-019  Lock alpha/beta performance contracts (evidence + contract framework)
DGR-020  Run controlled whole-model GGUF baseline (benchmark results & contracts)
DGR-024  Real generated-gRPC protocol harness (shard_runtime_server.py + tests)
DGR-026  split-GGUF provisioning outside /home (provision script + manifest + tests)
DGR-028  Numbered patch-stack apply & verify (llama_cpp_dependency.py + UPSTREAM_LOCK.json)
DGR-029  Native CMake skeleton + deterministic CPU lane (UPSTREAM_LOCK.json + cmake gating)

New modules:
  packages/node/meshnet_node/dgr_performance/  — performance contract framework
  packages/node/meshnet_node/split_gguf/        — split-GGUF manifest & provisioning
  scripts/provision_split_gguf.py               — artifact provisioning CLI
  tests/test_dgr_performance_contract.py        — contract validation tests
  tests/test_split_gguf_manifest.py             — manifest tests
  tests/test_split_gguf_provision.py            — provisioning tests
  tests/test_shard_runtime_harness.py           — gRPC harness tests

.scratch/distributed-gguf-runtime/evidence/DGR-020/contract-evaluation.json

@@ -0,0 +1,71 @@
+{
+  "contract_version": 1,
+  "fit_benefit": true,
+  "plan_id": "dgr-001-controlled-whole-model-baseline-v1",
+  "quality_lane_pass": false,
+  "rationale": [
+    "the near-lossless quality lane failed: the GGUF runtime disagrees with the safetensors reference beyond what near-lossless weights can explain",
+    "a meaningful speed benefit was measured",
+    "a meaningful fit benefit was measured"
+  ],
+  "recipes": [
+    {
+      "comparable": true,
+      "failures": 0,
+      "fit_benefit": false,
+      "incomparable_reason": "",
+      "lane": "quality",
+      "measurements": {
+        "aggregate_concurrency": 4,
+        "aggregate_throughput_speedup": 4.465,
+        "artifact_size_ratio": 0.9946,
+        "artifact_size_win": false,
+        "compared_prompts": 3,
+        "decode_speedup": 2.0171,
+        "exact_match_rate": 0.3333,
+        "expected_prompts": 3,
+        "failure_rate": 0.0,
+        "mean_similarity": 0.9471,
+        "resident_memory_ratio": 0.5742,
+        "ttft_ratio": 0.4586
+      },
+      "quality_pass": false,
+      "reasons": [
+        "single-request decode 2.02x reference (>= 1.25x) at TTFT ratio 0.46",
+        "aggregate throughput at concurrency 4 is 4.46x reference (>= 1.25x)",
+        "peak resident memory is 0.57x reference (<= 0.75x)",
+        "quality lane exact-match 0.33 / similarity 0.947 versus the reference (fail)"
+      ],
+      "recipe_id": "llama-cpp-near-lossless-quality",
+      "speed_benefit": false
+    },
+    {
+      "comparable": true,
+      "failures": 0,
+      "fit_benefit": true,
+      "incomparable_reason": "",
+      "lane": "performance-fit",
+      "measurements": {
+        "aggregate_concurrency": 4,
+        "aggregate_throughput_speedup": 4.825,
+        "artifact_size_ratio": 0.398,
+        "artifact_size_win": true,
+        "decode_speedup": 4.1931,
+        "failure_rate": 0.0,
+        "resident_memory_ratio": 0.2802,
+        "ttft_ratio": 0.5251
+      },
+      "quality_pass": null,
+      "reasons": [
+        "single-request decode 4.19x reference (>= 1.25x) at TTFT ratio 0.53",
+        "aggregate throughput at concurrency 4 is 4.83x reference (>= 1.25x)",
+        "peak resident memory is 0.28x reference (<= 0.75x)"
+      ],
+      "recipe_id": "llama-cpp-quantized-performance-fit",
+      "speed_benefit": true
+    }
+  ],
+  "speed_benefit": true,
+  "stop_condition_met": true,
+  "verdict": "stop"
+}