fix(shader): keep a focused plate's accent ring off its carved wells

A focused (accent-tinted) plate computed its wrapped specular line from the
full slope field — the plate's own roll PLUS every carve feature grouped into
it — so each well carved into the plate drew the same accent ring around
itself. On the designer's parameter pane that read as every control being
focused alongside the pane.

The wrap now runs on the plate's own roll only (the slope before the feature
loop); the carves keep the neutral directional glint an unfocused plate gives
them, which is exactly their term since the rim slope is zero on the face.
Fill-less tinted plates (the network cursor) are unchanged.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

 src/vk/shader2d.wgsl | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/vk/shader2d.wgsl b/src/vk/shader2d.wgsl
index e7f1218..842133a 100644
--- a/src/vk/shader2d.wgsl
+++ b/src/vk/shader2d.wgsl
@@ -530,6 +530,10 @@ fn plate_shade(frag: vec2f, vcol: vec4f) -> vec4f {
         // roll meets the face — then every carve's slope adds to it, and its
         // shoulder/fillet ambient term joins the roll's crest.
         var sv = gd.xy * roll_slope(f);
+        // The plate's OWN roll, kept apart from the carves added below: a
+        // focused plate's accent ring traces this alone (see the tinted
+        // branch), so the wells carved into it never wear the ring too.
+        let sv_rim = sv;
         var extra = PLATE_CREST * f * f * f;
         let f_off = u32(rrect_clip.p_host.x);
         let f_cnt = u32(rrect_clip.p_host.y);
@@ -559,9 +563,13 @@ fn plate_shade(frag: vec2f, vcol: vec4f) -> vec4f {
         // as painted frames). Neutral plates (w = 0) keep the directional
         // glint, byte-identical.
         let tw = rrect_clip.p_spec_tint.w;
-        var spec = roll_spec(sv);
         if (tw > 0.0) {
-            spec = roll_spec_wrap(sv);
+            // The wrap runs on the plate's own roll ONLY (sv_rim), never on
+            // the carves: with the full slope every well carved into a
+            // focused plate — each parameter control on the designer's
+            // parameter pane — drew its own accent ring, reading as if every
+            // control were focused alongside the pane.
+            let spec = roll_spec_wrap(sv_rim);
             // A FILL-LESS tinted plate is a pure focus ring (the network
             // cursor): the wrapped glint alone, on the plate's own roll — so
             // the line traces the same superellipse silhouette, radius
@@ -571,7 +579,16 @@ fn plate_shade(frag: vec2f, vcol: vec4f) -> vec4f {
             if (abs(base.a) < 0.004) {
                 return vec4f(rrect_clip.p_spec_tint.rgb, spec * strength * aa);
             }
+            // The carves keep the neutral directional glint an unfocused
+            // plate gives them (white, as p_spec_tint.rgb is for w = 0);
+            // sv_rim is zero on the face, so this is exactly their term.
+            let carve_spec = roll_spec(sv - sv_rim);
+            return vec4f(
+                base.rgb * shade + rrect_clip.p_spec_tint.rgb * (spec * strength) + vec3f(carve_spec * strength),
+                abs(base.a) * aa,
+            );
         }
+        let spec = roll_spec(sv);
         return vec4f(base.rgb * shade + rrect_clip.p_spec_tint.rgb * (spec * strength), abs(base.a) * aa);
     }