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/porting-steps-standalone.md

@@ -493,6 +493,10 @@ Current verified progress:
   `vendor/linuxcnc/`. This keeps G-code group conversion on the vendored
   LinuxCNC `interp_convert.cc` path instead of allowing the wrapper layer to
   grow another project-authored conversion implementation.
+- `docs/scope-and-baseline.md` records the current upstream LinuxCNC commit,
+  local tool versions, and fixture baseline. `tools/verify_upstream_baseline.sh`
+  now runs before vendor sync validation so extraction drift is checked against
+  the intended upstream HEAD, not an accidental checkout change.
 
 ## Phase 4: Port INI Parsing Without Editing Upstream
 

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

@@ -0,0 +1,64 @@
+# 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.

wasm-port/tests/native/verify_native_probes.sh

@@ -9,6 +9,7 @@ GCODE_ERROR_FIXTURE_DIR="$ROOT_DIR/tests/fixtures/gcode_errors"
 CANON_ERROR_FIXTURE_DIR="$ROOT_DIR/tests/fixtures/canon_errors"
 NAMEDPARAM_INI_FIXTURE="$ROOT_DIR/tests/fixtures/ini/namedparams.ini"
 
+"$ROOT_DIR/tools/verify_upstream_baseline.sh"
 "$ROOT_DIR/tools/verify_vendor_sync.sh"
 "$ROOT_DIR/tools/verify_no_standalone_cnc_semantics.sh"
 "$ROOT_DIR/tools/build_native_probes.sh"

wasm-port/tools/upstream-baseline.txt

@@ -0,0 +1 @@
+60597ee0718873d2449058c824262a275e5e4bad

wasm-port/tools/verify_upstream_baseline.sh

@@ -0,0 +1,34 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "$0")/.." && pwd)"
+UPSTREAM_DIR="$ROOT_DIR/../linuxcnc"
+BASELINE_FILE="$ROOT_DIR/tools/upstream-baseline.txt"
+
+if [[ ! -d "$UPSTREAM_DIR/.git" ]]; then
+  echo "missing upstream git repository: $UPSTREAM_DIR" >&2
+  exit 1
+fi
+
+if [[ ! -f "$BASELINE_FILE" ]]; then
+  echo "missing upstream baseline file: $BASELINE_FILE" >&2
+  exit 1
+fi
+
+expected="$(sed -n '1p' "$BASELINE_FILE" | tr -d '[:space:]')"
+actual="$(git -C "$UPSTREAM_DIR" rev-parse HEAD)"
+
+if [[ -z "$expected" ]]; then
+  echo "empty upstream baseline file: $BASELINE_FILE" >&2
+  exit 1
+fi
+
+if [[ "$actual" != "$expected" ]]; then
+  echo "upstream baseline mismatch:" >&2
+  echo "  expected: $expected" >&2
+  echo "  actual:   $actual" >&2
+  echo "Update tools/upstream-baseline.txt and docs/scope-and-baseline.md only after an intentional upstream sync." >&2
+  exit 1
+fi
+
+echo "upstream baseline validation complete"