ref(upstream): FULL TREE — Deep-Spark xllm (1470) + ds_vllm csrc/models (703)

Replaces cherry-picked upstream_ref with complete source trees.

xllm/ — Iluvatar official C++ inference engine (15MB, 1470 files)
  Complete: kernels → layers → models → runtime → scheduler → api
  Excluded: .git, binary images, third_party submodule checkouts

ds_vllm/ — Iluvatar official vllm fork (8MB, 703 files)
  Included: csrc/ (ALL CUDA kernels), fused_moe/, qwen3_5 model, _custom_ops
  Excluded: tests, benchmarks, docs, examples (not needed for reference)

Critical call chains now fully traceable:
  MoE: moe_topk_softmax_kernels.cuh → ixformer.h → fused_moe.cpp → layer
  GDN: qwen3_gated_delta_net_base.cpp → qwen3_5_gated_delta_net.cpp
  Attention: ixformer.h → xllm_paged_attention → attention.cpp

upstream_ref/xllm/.agents/skills/git-workflow/SKILL.md

@@ -0,0 +1,49 @@
+---
+name: git-workflow
+description: Use when the task involves Git operations for the public xLLM repository, including choosing branch or tag names, preparing commits and pull requests, backporting fixes, checking repo-specific review expectations, or drafting commit messages from actual diffs.
+---
+
+# Git Workflow
+
+Use xLLM repo reality, not generic Git habits.
+
+## Reference Map
+
+Load only the file that matches the user's immediate Git task.
+
+| File | What it is for | When to load it |
+| --- | --- | --- |
+| `references/source-of-truth.md` | Repo-specific source priority and canonical files to consult | Load first when repo docs, local state, and user wording may disagree |
+| `references/branch-naming.md` | Branch naming patterns and default branch conventions | Load when the user asks how to name a branch or which branch to branch from |
+| `references/development-flow.md` | Day-to-day fork, sync, branch, validate, and push flow | Load when the user asks for normal development steps from local change to push |
+| `references/pr-review.md` | PR targeting, PR scope, and review expectations | Load when the task is about opening a PR, choosing the target branch, or deciding who should review |
+| `references/release-layout.md` | Release branch and tag shapes used by xLLM | Load when the task mentions release branches, release tags, or patch version naming |
+| `references/backport-flow.md` | Preferred backport and hotfix flow for released lines | Load when the task mentions cherry-picks, hotfixes, or fixing an already released branch |
+| `references/commit-format.md` | Commit title/body conventions and xLLM-style examples | Load when the user asks for a commit message, commit style guidance, or message cleanup |
+
+## Workflow
+
+1. Decide which subtask the user actually needs.
+2. Read `references/source-of-truth.md` when you need repo-specific confirmation.
+3. Then load only the most relevant task file from the table above.
+4. For commit message drafting, run `bash scripts/collect_git_context.sh [--staged|--all|--unstaged]` before writing the final message.
+5. Draft commit messages from the actual diff, not from filenames alone.
+6. If one diff mixes unrelated concerns, recommend splitting the commit instead of forcing one vague summary.
+7. Default PR targets to `main` unless the task is clearly a release or backport flow.
+8. For released lines, prefer landing on `main` first and then backporting unless the user explicitly wants a direct hotfix flow.
+
+## Output
+
+Return the smallest useful answer for the user's Git task:
+
+- workflow questions: concrete branch, tag, PR, or backport steps
+- commit message requests: `<type>: <subject>` plus an optional short bullet body
+- repo-convention questions: current xLLM-specific guidance, not generic Git advice
+
+## Quick Checks
+
+- branch names match xLLM style such as `feat/<topic>`, `bugfix/<topic>`, or `release/vX.Y.Z`
+- PR target is `main` unless this is a release or backport task
+- commit title matches the dominant change in the diff
+- release tags use semantic versions such as `v0.9.0` or `v0.9.1`
+- owner-review expectations come from `.github/CODEOWNERS` when relevant