feat(theme-studio): explicit absolute-vs-relative face height kind

JSON collapses 2.0 to 2 on save, so a height's number type can't say whether it's a fixed 1/10pt value or a relative multiplier. The face model now carries an explicit heightMode field (abs/rel) through seed, save/load, and export. build-theme.el coerces :height from the kind: abs exports an integer, rel a float, so a relative 2.0 renders as 2.0, never 2.

Faces saved before the field existed infer the kind once on load (JS: integer to abs, fractional to rel; Python keeps the authored type, so a float 2.0 seed stays relative) and persist it on the next save. The mode-line seed carries abs explicitly, and WIP.json's eight seeded heights are stamped with their kinds. Regenerating the theme from the stamped WIP.json produces an identical WIP-theme.el, so the round-trip holds.

1 files changed, 16 insertions, 3 deletions

diff --git a/scripts/theme-studio/build-theme.el b/scripts/theme-studio/build-theme.el
index e3721499..3e488d36 100644
--- a/scripts/theme-studio/build-theme.el
+++ b/scripts/theme-studio/build-theme.el
@@ -137,14 +137,27 @@ yields a (:color C :style S) plist.  Tolerates the legacy boolean form."
                    (t                t))))
           (t t))))
 
+(defun build-theme/--height (obj)
+  "Coerce OBJ's height from its explicit kind field, or nil when unset.
+heightMode \"abs\" yields an integer :height (fixed 1/10pt); \"rel\" yields a
+float multiplier -- even when the number arrives integral, because JSON
+collapses 2.0 to 2 on save, so the number type can never carry the kind.  A
+spec without a recognized heightMode keeps the number as parsed (legacy).
+The identity height 1/1.0 emits nothing under every kind."
+  (let ((height (build-theme/--obj-get obj 'height))
+        (kind (build-theme/--obj-get obj 'heightMode)))
+    (when (and (numberp height) (/= height 1.0))
+      (cond ((equal kind "abs") (truncate height))
+            ((equal kind "rel") (float height))
+            (t height)))))
+
 (defun build-theme/--attrs (obj)
   "Build a face-attribute plist from face-spec alist OBJ, in canonical order.
 Reads the full attribute model -- inherit, family, fg/bg, distant-foreground,
 weight, slant, height, underline, overline, strike-through, box, inverse-video,
 extend -- and tolerates the older boolean bold/italic/underline/strike fields.
 Only attributes that are set appear, so a blank face yields nil."
-  (let* ((height (build-theme/--obj-get obj 'height))
-         (family (build-theme/--obj-get obj 'family))
+  (let* ((family (build-theme/--obj-get obj 'family))
          (pairs
           (list
            (cons :inherit            (build-theme/--inherit-symbol (build-theme/--obj-get obj 'inherit)))
@@ -154,7 +167,7 @@ Only attributes that are set appear, so a blank face yields nil."
            (cons :distant-foreground (build-theme/--obj-get obj 'distant-fg))
            (cons :weight             (build-theme/--weight obj))
            (cons :slant              (build-theme/--slant obj))
-           (cons :height             (and (numberp height) (/= height 1.0) height))
+           (cons :height             (build-theme/--height obj))
            (cons :underline          (build-theme/--underline obj))
            (cons :overline           (build-theme/--line-attr (build-theme/--obj-get obj 'overline)))
            (cons :strike-through     (build-theme/--line-attr (build-theme/--obj-get obj 'strike)))