fix(skills): full Principled BSDF v2 socket table; drop dead 3.x socket fallbacks

The procedural-materials skill documented only Specular -> Specular IOR
Level, and taught a set_specular shim whose 3.x branch never runs on a
supported version. 17 examples carried the same dead pattern,
inputs.get("Emission Color") or inputs["Emission"].

The skill now has the full 3.x -> 4.0+ table, measured on 4.5.14 and
5.2.1:
- Emission, Subsurface, Clearcoat, Sheen and Transmission renames;
- Subsurface Color and Transmission Roughness removed;
- Specular Tint and Sheen Tint are now RGBA;
- the v2-only inputs, and Thin Wall, which is 5.2 only.
It quotes the exact KeyError and adds a common-mistakes entry. The 22
fallbacks in examples now use the 4.0+ name directly.

The swatch-grid shim stays, because witnessing the rename is that
example's contract. Mix-node Factor/Fac fallbacks also stay: ShaderNodeMixRGB
still names it Fac, so those branches are live. Verified on 5.2.1 and 4.5.14:
mesh-hygiene-audit --output (cycles), sky-texture-sun-elevation and
uv-layer-grid all exit 0.

Closes #382

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: TMHSDigital <154358121+TMHSDigital@users.noreply.github.com>

Author: TMHSDigital

examples/cross-version-property-delete/cross_version_property_delete.py

@@ -215,7 +215,7 @@ def principled(name, color, metallic, roughness, emission=None, strength=4.5):
     bsdf.inputs["Metallic"].default_value = metallic
     bsdf.inputs["Roughness"].default_value = roughness
     if emission is not None:
-        sock = bsdf.inputs.get("Emission Color") or bsdf.inputs["Emission"]
+        sock = bsdf.inputs["Emission Color"]
         sock.default_value = emission
         bsdf.inputs["Emission Strength"].default_value = strength
     return mat

examples/degenerate-bevel-weld/degenerate_bevel_weld.py

@@ -232,7 +232,7 @@ def make_material(name, rgb, rough=0.45, metallic=0.35, emit=None, estr=0.0):
     b.inputs["Roughness"].default_value = rough
     b.inputs["Metallic"].default_value = metallic
     if emit is not None:
-        sock = b.inputs.get("Emission Color") or b.inputs["Emission"]
+        sock = b.inputs["Emission Color"]
         sock.default_value = (*emit, 1.0)
         b.inputs["Emission Strength"].default_value = estr
     return mat

examples/export-preset-axis/export_preset_axis.py

@@ -287,7 +287,7 @@ def build():
         principled("CabinetPaint", (0.20, 0.30, 0.25, 1.0), 0.0, 0.5),
     )
     bsdf = mats[MAT_LAMP].node_tree.nodes["Principled BSDF"]
-    sock = bsdf.inputs.get("Emission Color") or bsdf.inputs["Emission"]
+    sock = bsdf.inputs["Emission Color"]
     sock.default_value = (1.0, 0.012, 0.006, 1.0)
     bsdf.inputs["Emission Strength"].default_value = 3.0
     for m in mats:
@@ -566,7 +566,7 @@ def light(scene, name, loc, energy, size, col, target):
 def gizmo_material(name, color):
     mat = principled(name, color, 0.0, 0.35)
     bsdf = mat.node_tree.nodes["Principled BSDF"]
-    sock = bsdf.inputs.get("Emission Color") or bsdf.inputs["Emission"]
+    sock = bsdf.inputs["Emission Color"]
     sock.default_value = color
     bsdf.inputs["Emission Strength"].default_value = 0.25
     return mat

examples/gltf-export-roundtrip/gltf_export_roundtrip.py

@@ -172,7 +172,7 @@ def pbr(name, base, metallic, roughness, emission=None, strength=0.0):
         b.inputs["Metallic"].default_value = metallic
         b.inputs["Roughness"].default_value = roughness
         if emission is not None:
-            sock = b.inputs.get("Emission Color") or b.inputs["Emission"]
+            sock = b.inputs["Emission Color"]
             sock.default_value = (*emission, 1.0)
             b.inputs["Emission Strength"].default_value = strength
         return mat

examples/gltf-skin-roundtrip/gltf_skin_roundtrip.py

@@ -803,7 +803,7 @@ def pbr(name, base, metallic, roughness, emission=None, strength=0.0):
         b.inputs["Metallic"].default_value = metallic
         b.inputs["Roughness"].default_value = roughness
         if emission is not None:
-            sock = b.inputs.get("Emission Color") or b.inputs["Emission"]
+            sock = b.inputs["Emission Color"]
             sock.default_value = (*emission, 1.0)
             b.inputs["Emission Strength"].default_value = strength
         return mat

examples/gn-socket-rename/gn_socket_rename.py

@@ -249,7 +249,7 @@ def principled(name, color, metallic, roughness, emission=None):
     bsdf.inputs["Metallic"].default_value = metallic
     bsdf.inputs["Roughness"].default_value = roughness
     if emission is not None:
-        sock = bsdf.inputs.get("Emission Color") or bsdf.inputs["Emission"]
+        sock = bsdf.inputs["Emission Color"]
         sock.default_value = emission
         bsdf.inputs["Emission Strength"].default_value = 0.12
     return mat
@@ -405,7 +405,7 @@ def dress_gauge(copper, steel):
     enabled_sock(base, "inputs", "A").default_value = (0.93, 0.42, 0.08, 1.0)
     enabled_sock(base, "inputs", "B").default_value = (0.05, 0.018, 0.006, 1.0)
     nt.links.new(enabled_sock(base, "outputs", "Result"), bsdf.inputs["Base Color"])
-    emit = bsdf.inputs.get("Emission Color") or bsdf.inputs["Emission"]
+    emit = bsdf.inputs["Emission Color"]
     nt.links.new(enabled_sock(base, "outputs", "Result"), emit)
     # Brushed, the copper reflects less of the key and went brown at
     # thumbnail size; a little more of its own colour keeps it copper.

examples/light-link-studio/light_link_studio.py

@@ -80,7 +80,7 @@ def _principled(name, rgb, rough, metallic=0.0, emit=None, estr=0.0):
     b.inputs["Roughness"].default_value = rough
     b.inputs["Metallic"].default_value = metallic
     if emit is not None:
-        sock = b.inputs.get("Emission Color") or b.inputs["Emission"]
+        sock = b.inputs["Emission Color"]
         sock.default_value = (*emit, 1.0)
         b.inputs["Emission Strength"].default_value = estr
     return mat

examples/lightmap-uv-channel/lightmap_uv_channel.py

@@ -698,7 +698,7 @@ def make_material(name, rgb, rough=0.6, metallic=0.0, emit=None, estr=0.0,
     b.inputs["Roughness"].default_value = rough
     b.inputs["Metallic"].default_value = metallic
     if emit is not None:
-        sock = b.inputs.get("Emission Color") or b.inputs["Emission"]
+        sock = b.inputs["Emission Color"]
         sock.default_value = (*emit, 1.0)
         b.inputs["Emission Strength"].default_value = estr
     if grain or bump:

examples/lod-decimate-chain/lod_decimate_chain.py

@@ -427,7 +427,7 @@ def pbr(name, base, metallic, roughness, emission=None, strength=0.0):
         b.inputs["Metallic"].default_value = metallic
         b.inputs["Roughness"].default_value = roughness
         if emission is not None:
-            sock = b.inputs.get("Emission Color") or b.inputs["Emission"]
+            sock = b.inputs["Emission Color"]
             sock.default_value = (*emission, 1.0)
             b.inputs["Emission Strength"].default_value = strength
         return mat

examples/mesh-hygiene-audit/mesh_hygiene_audit.py

@@ -235,11 +235,11 @@ def make_material(name, rgb, rough=0.45, metallic=0.0, emit=None, estr=0.0,
     b.inputs["Roughness"].default_value = rough
     b.inputs["Metallic"].default_value = metallic
     if coat:
-        sock = b.inputs.get("Coat Weight") or b.inputs.get("Clearcoat")
+        sock = b.inputs["Coat Weight"]
         if sock is not None:
             sock.default_value = coat
     if emit is not None:
-        sock = b.inputs.get("Emission Color") or b.inputs["Emission"]
+        sock = b.inputs["Emission Color"]
         sock.default_value = (*emit, 1.0)
         b.inputs["Emission Strength"].default_value = estr
     return mat
@@ -261,7 +261,7 @@ def add_backface_witness(mat, rgb=(0.85, 0.002, 0.004), strength=0.35):
     back = nt.nodes.new("ShaderNodeBsdfPrincipled")
     back.inputs["Base Color"].default_value = (*rgb, 1.0)
     back.inputs["Roughness"].default_value = 0.5
-    sock = back.inputs.get("Emission Color") or back.inputs["Emission"]
+    sock = back.inputs["Emission Color"]
     sock.default_value = (*rgb, 1.0)
     back.inputs["Emission Strength"].default_value = strength
     mix = nt.nodes.new("ShaderNodeMixShader")