按推荐建议，继续执行

结论：记录 LinuxCNC 上游 commit 与本地构建/fixture 基线，新增 upstream baseline 验证并接入 native 验证，确保 vendored 源码同步绑定到明确的 LinuxCNC 源程序版本。

wasm-port/docs/scope-and-baseline.md

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+# Scope And Baseline
+
+## Upstream Source Baseline
+
+The standalone port currently treats `../linuxcnc/` as the read-only upstream
+source provider.
+
+- Upstream repository: `../linuxcnc`
+- Upstream branch at baseline: `master`
+- Upstream commit: `60597ee0718873d2449058c824262a275e5e4bad`
+- Upstream subject: `Merge pull request #4043 from grandixximo/docs-inkscape-rsvg-shim`
+- Upstream author: `andypugh`
+- Upstream commit date: `2026-05-19T15:26:50+01:00`
+
+The upstream working tree is allowed to contain unrelated local files, but the
+vendored-source validation is tied to the commit above. If upstream HEAD
+changes, re-run extraction intentionally and update this baseline in the same
+change.
+
+## Local Build Assumptions
+
+- C++ compiler: `g++ (Debian 14.2.0-19) 14.2.0`
+- C compiler: `gcc (Debian 14.2.0-19) 14.2.0`
+- Python: `Python 3.13.5`
+- Node.js: `v20.19.2`
+- Emscripten: `emcc 3.1.69`
+
+## Current Fixture Baseline
+
+The native standalone validation currently uses the fixture set under
+`tests/fixtures/`.
+
+G-code fixture coverage includes:
+
+- linear traverse and feed
+- arc semantics
+- modal incremental and absolute distance modes
+- position parameters
+- canned cycles
+- coordinate offsets
+- feed and motion control modes
+- probe semantics
+- spindle-synchronized threading and rigid tap
+- NURBS G5 and G6
+- spindle orient
+- tool semantics and tool table setup
+- named and numbered parameters
+- O-word subroutines
+- program-end modal reset
+- canonical runtime edge calls
+
+Negative fixture coverage includes:
+
+- zero-feed `G1`
+- arc radius mismatch
+- zero-radius arc
+- read-only named parameter writes
+- read-only numbered parameter writes
+- missing tool
+- missing tool length offset
+
+Machine baseline is still limited to standalone interpreter and trajectory
+planner probes. Full 3-axis, non-trivial kinematics, and 5-axis machine
+baselines remain future work.