Update reference SX spec to match sx.js macros branch (CSSX, dict literals, new primitives)

- eval.sx: Add defstyle, defkeyframes, defhandler special forms; add ho-for-each
- parser.sx: Add dict {...} literal parsing and quasiquote/unquote sugar
- primitives.sx: Add parse-datetime, split-ids, css, merge-styles primitives
- render.sx: Add StyleValue handling, SVG filter elements, definition forms in render, fix render-to-html to handle HTML tags directly
- bootstrap_js.py: Add StyleValue type, buildKeyframes, isEvery platform helper, new primitives (format-date, parse-datetime, split-ids, css, merge-styles), dict/quasiquote parser, expose render functions as primitives
- sx-ref.js: Regenerated — 132/132 tests passing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

shared/sx/ref/parser.sx

@@ -18,11 +18,13 @@
 ;;   ident      → [a-zA-Z_~*+\-><=/!?&] [a-zA-Z0-9_~*+\-><=/!?.:&]*
 ;;   comment    → ';' to end of line (discarded)
 ;;
-;; Quote sugar (optional — not used in current SX):
-;;   '(expr)     → (quote expr)
+;; Dict literal:
+;;   {key val ...}  → dict object (keys are keywords or expressions)
+;;
+;; Quote sugar:
 ;;   `(expr)     → (quasiquote expr)
-;;   ~(expr)     → (unquote expr)
-;;   ~@(expr)    → (splice-unquote expr)
+;;   ,(expr)     → (unquote expr)
+;;   ,@(expr)    → (splice-unquote expr)
 ;; ==========================================================================
 
 
@@ -81,6 +83,37 @@
                       (advance-pos!)
                       (scan-next))
 
+                ;; Open brace (dict literal)
+                (= ch "{")
+                  (do (append! tokens (list "lbrace" "{" line col))
+                      (advance-pos!)
+                      (scan-next))
+
+                ;; Close brace
+                (= ch "}")
+                  (do (append! tokens (list "rbrace" "}" line col))
+                      (advance-pos!)
+                      (scan-next))
+
+                ;; Quasiquote sugar
+                (= ch "`")
+                  (do (advance-pos!)
+                      (let ((inner (scan-next-expr)))
+                        (append! tokens (list "quasiquote" inner line col))
+                        (scan-next)))
+
+                ;; Unquote / splice-unquote
+                (= ch ",")
+                  (do (advance-pos!)
+                      (if (and (< pos len-src) (= (nth source pos) "@"))
+                        (do (advance-pos!)
+                            (let ((inner (scan-next-expr)))
+                              (append! tokens (list "splice-unquote" inner line col))
+                              (scan-next)))
+                        (let ((inner (scan-next-expr)))
+                          (append! tokens (list "unquote" inner line col))
+                          (scan-next))))
+
                 ;; Keyword
                 (= ch ":")
                   (do (append! tokens (scan-keyword)) (scan-next))
@@ -229,6 +262,10 @@
           (do (set! pos (inc pos))
               (parse-list tokens "rbracket"))
 
+        "lbrace"
+          (do (set! pos (inc pos))
+              (parse-dict tokens))
+
         "string"  (do (set! pos (inc pos)) (nth tok 1))
         "number"  (do (set! pos (inc pos)) (nth tok 1))
         "boolean" (do (set! pos (inc pos)) (nth tok 1))
@@ -261,6 +298,28 @@
       items)))
 
 
+(define parse-dict
+  (fn (tokens)
+    ;; Parse {key val key val ...} until "rbrace" token.
+    ;; Returns a dict (plain object).
+    (let ((result (dict)))
+      (define parse-dict-loop
+        (fn ()
+          (if (>= pos (len tokens))
+            (error "Unterminated dict")
+            (if (= (first (nth tokens pos)) "rbrace")
+              (do (set! pos (inc pos)) nil)  ;; done
+              (let ((key-expr (parse-expr tokens))
+                    (key-str  (if (= (type-of key-expr) "keyword")
+                                (keyword-name key-expr)
+                                (str key-expr)))
+                    (val-expr (parse-expr tokens)))
+                (dict-set! result key-str val-expr)
+                (parse-dict-loop))))))
+      (parse-dict-loop)
+      result)))
+
+
 ;; --------------------------------------------------------------------------
 ;; Serializer — AST → SX source text
 ;; --------------------------------------------------------------------------