feat(3d): gl1 shim M4+M6+M7 — GLU quadrics, production link, stub retired; 47/47 parity

- gl1_glu: gluCylinder/gluDisk/gluSphere per the SGI GLU reference
  tessellation (sin/cos phase, strip emission order, pole fans — Apple's
  GLU derives from the same source, so vertices match the goldens);
  emission goes through the public glBegin/glVertex entry points so
  quadrics record into display lists
- glLineWidth>1 one-time warning (browsers clamp to 1; affected coverage
  stays under the parity floor — zero floors.json overrides needed)
- production link site: build-kicad-target.sh now compiles wasm/gl1 from
  sources.txt and applies wrapped_symbols.txt --wrap flags (same manifests
  as the test harness); kicad_editor's RENDER_3D_OPENGL links against the
  real emulation layer instead of no-ops
- wasm/stubs/gl_ffp_stub.c deleted (role fully superseded; history in git)
- docs: 3d-regression README port-status section (floor-blind small
  geometry + line-width caveats), harness comments de-red-stated

Parity: 47/47 under the 0.02 floor, zero overrides. Native golden path
byte-identical to bb0e238 (whose gate ran green) — scenarios/, native/,
baseline/, manifest, floors, spec all untouched by the port.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/3d-regression/README.md

@@ -13,9 +13,10 @@ compiled two ways:
   the vendored glad loader). Renders each scenario into a fixed 800×600
   offscreen FBO (`GL_RGBA8` + `GL_DEPTH24_STENCIL8`, the
   `EDA_3D_CANVAS::RenderToFrameBuffer` recipe) → **golden baselines**.
-- **wasm/** — the same scenario TUs compiled with em++ (planned; red state
-  first: linked against `wasm/stubs/gl_ffp_stub.c` no-ops, every render blank
-  until the port makes them green).
+- **wasm/** — the same scenario TUs compiled with em++, linked against the
+  **`wasm/gl1`** GL1→WebGL2 emulation layer (the port itself — see
+  `wasm/gl1/README.md`). Since the port landed, all 47 scenarios render under
+  the parity floor with zero per-scenario overrides.
 
 ## Directory layout
 
@@ -74,13 +75,22 @@ every run, so a scenario registry change can't silently drift past the
 baselines. Scenario names are append-only — never rename or renumber (they are
 the PNG names and the WebGL test IDs).
 
-## TDD red state
+## Port status (was: TDD red state)
 
-Once `wasm/` exists, the Playwright spec (`tests/e2e/3d-webgl.spec.ts`) is
-capture-only and stays green; the red signal is `npm run 3d:check:parity`
-reporting ~100% changed for every scenario. Port progress = scenarios dropping
-out of that report. `glLineWidth > 1` (model bbox scenario) has no WebGL
-equivalent — expect that one to need quad emulation to go green.
+The suite drove the port TDD-style: the harness started against no-op FFP
+stubs (~100% changed everywhere), and the `wasm/gl1` emulation layer ground
+the parity report down milestone by milestone (substrate → lighting →
+display lists/arrays → GLU quadrics). **Current state: 47/47 under the 0.02
+parity floor, no floors.json overrides needed.**
+
+Two caveats the parity floor cannot see (verified by eyeballing renders):
+
+- Small-geometry scenarios (the GLU arrows, the spheres gizmo, sparse grids)
+  fit under the floor even when absent — a regression there needs the
+  triptych/eyeball check, not just the report.
+- `glLineWidth > 1` is clamped to 1 by browsers (gizmo axes, native width
+  2–4 lines render thinner); the affected coverage is small enough to stay
+  under the floor.
 
 ## Scenario tiers (47 scenarios)
 

tests/3d-regression/wasm/3d_webgl_test.cpp

@@ -1,8 +1,8 @@
 /**
  * 3D-renderer WebGL test harness (WASM) — runs the shared scenarios
- * (tests/3d-regression/scenarios/) in the browser. Today the legacy GL
- * surface is wasm/stubs/gl_ffp_stub.c no-ops, so every scenario renders a
- * black canvas: the TDD red state the WebGL port turns green.
+ * (tests/3d-regression/scenarios/) in the browser. The legacy GL surface is
+ * implemented by the wasm/gl1 GL1->WebGL2 emulation layer; the parity level
+ * (npm run 3d:check:parity) compares these renders against the native goldens.
  *
  * Unlike the GAL harness this needs no wx window: the renderer draws into
  * whatever context is current, so a direct emscripten WebGL2 context on

tests/3d-regression/wasm/Makefile

@@ -1,11 +1,11 @@
-# Makefile for the 3D-renderer WebGL test harness (WASM) — TDD RED STATE.
+# Makefile for the 3D-renderer WebGL test harness (WASM).
 #
 # Compiles the SAME shared scenarios + real KiCad 3D-viewer TUs as the native
-# golden generator (tests/3d-regression/native/CMakeLists.txt), but links the
-# fixed-function GL surface against wasm/stubs/gl_ffp_stub.c no-ops — exactly
-# how the production kicad build satisfies RENDER_3D_OPENGL's link today.
-# Every scenario therefore renders BLANK until the WebGL port replaces those
-# stubs; `npm run 3d:check:parity` is the port-progress meter.
+# golden generator (tests/3d-regression/native/CMakeLists.txt), linking the
+# fixed-function GL surface against the wasm/gl1 GL1->WebGL2 emulation layer —
+# exactly how the production kicad build satisfies RENDER_3D_OPENGL's link.
+# `npm run 3d:check:parity` compares the browser renders against the native
+# goldens (47/47 under floor since the port).
 #
 # Usage:
 #   make                    # Build
@@ -96,7 +96,7 @@ TESTIMPL_SRCS = ../native/board_adapter_test_impl.cpp \
                 ../native/render3d_test_accessor.cpp
 
 # Same real-KiCad TU list as the native CMakeLists (minus glad — Emscripten
-# provides the modern GL surface, gl_ffp_stub.c the legacy one).
+# provides the modern GL surface, wasm/gl1 the legacy one).
 KICAD_3D_SRCS = \
     $(KICAD_ROOT)/3d-viewer/common_ogl/ogl_utils.cpp \
     $(KICAD_ROOT)/3d-viewer/3d_rendering/image.cpp \