docs(bench): add the v1.3.0 -> v1.4.0 correctness A/B gate to the README benchmark lanes

Ran benchmarks/compare_versions.py against the v1.3.0 tag: 21/21 on both versions, 0 fixed / 0 regressed - the v1.4.0 feature+infra work introduced no correctness regressions. Main README gains lane 4 (version A/B, with the historical v1.0.0 -> v1.1.0 contrast); benchmarks/README records the release-gate result and drops the stale 'performance coming' stub.

Co-authored-by: Cursor <cursoragent@cursor.com>

README.md

@@ -101,7 +101,35 @@ python -m benchmarks.perf_suite --out benchmarks/results/published/perf-ezdxf.js
 python -m benchmarks.render_perf_chart
 ```
 
-### 4 · Source-reviewed capability rubric (context)
+### 4 · Version A/B — every release re-proves correctness
+
+`compare_versions.py` runs the same 21 deterministic, headless correctness
+checks against the previous release tag and the current tree — each check in
+its own subprocess, so a hard crash counts as a miss instead of killing the
+run.
+
+**v1.4.0 release gate** (baseline `v1.3.0`, report:
+[`ab-v1.3.0-vs-v1.4.0.json`](benchmarks/results/published/ab-v1.3.0-vs-v1.4.0.json)):
+
+| Version | Checks passing | Pass rate | Fixed | Regressed |
+|---|---:|---:|---:|---:|
+| v1.3.0 (baseline) | 21 / 21 | 100 % | — | — |
+| **v1.4.0** (this release) | **21 / 21** | **100 %** | 0 | **0** |
+
+v1.4.0 added CI, packaging, benchmarks, tool profiles, paper space, ISO 286
+fits and opt-in 3D solids **without breaking a single correctness check**.
+For contrast, the same suite caught the v1.0.0 → v1.1.0 jump:
+
+| Version | Checks passing | Pass rate |
+|---|---:|---:|
+| v1.0.0 (first public release) | 8 / 21 | 38.1 % |
+| v1.1.0 | 21 / 21 | 100 % |
+
+```bash
+python benchmarks/compare_versions.py v1.3.0 --json ab.json
+```
+
+### 5 · Source-reviewed capability rubric (context)
 
 ![Source-reviewed AutoCAD MCP capability benchmark](docs/assets/autocad-mcp-benchmark.svg)
 

benchmarks/README.md

@@ -121,6 +121,20 @@ python benchmarks/compare_versions.py v1.0.0     # vs a tag/ref
 python benchmarks/compare_versions.py --json results.json
 ```
 
+### Result — v1.4.0 vs v1.3.0 (release gate)
+
+21 checks, ezdxf backend, one subprocess per check. Machine-readable report:
+[`results/published/ab-v1.3.0-vs-v1.4.0.json`](results/published/ab-v1.3.0-vs-v1.4.0.json).
+
+| Version | Checks passing | Pass rate | Fixed | Regressed |
+|---------|----------------|-----------|-------|-----------|
+| **v1.3.0** (baseline)     | 21 / 21 | 100 % | — | — |
+| **v1.4.0** (this release) | 21 / 21 | 100 % | 0 | **0** |
+
+The v1.4.0 feature and infrastructure work (CI, packaging, competitor lane,
+tool profiles, paper space, ISO 286 fits, opt-in solids) introduced **zero
+correctness regressions**.
+
 ### Result — v1.1.0 vs v1.0.0 (`origin/main`, commit 15fa2bc)
 
 21 checks, ezdxf backend, CPython 3.14, one subprocess per check.
@@ -167,8 +181,5 @@ not a cherry-picked list of failures; the baseline genuinely does basic CAD work
 - COM-backend behaviour is not covered here (no live AutoCAD); see the mocked-COM
   suites in `tests/`.
 
-## Performance (throughput) — coming
+Model-by-model tool-call success rates remain future work; scale/throughput
-
+numbers live in the headless performance lane above.
-Scale / throughput numbers (1k–100k entities, render timings, model-by-model
-tool-call success rate) are tracked in the main README and will be published here
-with a hardware footprint.

benchmarks/results/published/ab-v1.3.0-vs-v1.4.0.json

@@ -0,0 +1,140 @@
+{
+  "summary": {
+    "baseline_ref": "v1.3.0",
+    "total": 21,
+    "old_pass": 21,
+    "new_pass": 21,
+    "old_pct": 100.0,
+    "new_pct": 100.0,
+    "fixed": 0,
+    "regressed": 0
+  },
+  "rows": [
+    {
+      "check": "core_line_length",
+      "category": "Core",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "core_circle_radius",
+      "category": "Core",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "core_layer_create",
+      "category": "Core",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "core_polyline_closed",
+      "category": "Core",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "core_linear_dim",
+      "category": "Core",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "core_save_dxf_roundtrip",
+      "category": "Core",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "dim_aligned_no_error",
+      "category": "Dimensions",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "dim_angular_no_error",
+      "category": "Dimensions",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "array_polar_360_distinct",
+      "category": "Modify",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "point_intersection_line_line",
+      "category": "Geometry",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "point_tangent_external",
+      "category": "Geometry",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "arc_has_length",
+      "category": "Query",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "arc_select_by_length",
+      "category": "Query",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "ezdxf_bounding_box",
+      "category": "Query",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "mtext_rotation_roundtrip",
+      "category": "Entities",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "screenshot_png",
+      "category": "Render",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "dim_overlap_critique_fires",
+      "category": "Quality gate",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "iso13567_dim_layer",
+      "category": "Quality gate",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "construction_left_iso_caught",
+      "category": "Quality gate",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "gear_no_self_overlap",
+      "category": "Engineering",
+      "old": "pass",
+      "new": "pass"
+    },
+    {
+      "check": "center_linetype_applied",
+      "category": "Entities",
+      "old": "pass",
+      "new": "pass"
+    }
+  ]
+}