Fix Pretext island: library functions inside define-library begin block

Root cause: sx_insert_near placed break-lines-greedy, pretext-position-line,
pretext-layout-lines OUTSIDE the define-library begin block. The bytecode
compiler only compiles forms inside begin as STORE_GLOBAL — forms outside
are invisible to the browser VM.

Fix: moved all function definitions inside (begin ...) of (define-library).
Bytecode now includes all 17 functions (11K compiled, was 9K).

Browser load-sxbc: simplified VmSuspended handling — just catch and
continue, since STORE_GLOBAL ops already ran before the import OP_PERFORM.
sync_vm_to_env copies them to global_env.

Island now calls break-lines and pretext-layout-lines from bytecode-compiled
library — runs on VM, not CEK interpreter.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

shared/static/wasm/sx/hs-compiler.sx

@@ -240,18 +240,22 @@
           ((prop (nth ast 1)) (value (hs-to-sx (nth ast 2))))
           (if
             (= (len ast) 5)
-            (list
-              (quote hs-transition)
-              (hs-to-sx (nth ast 4))
-              prop
-              value
-              (nth ast 3))
-            (list
-              (quote hs-transition)
-              (hs-to-sx (nth ast 3))
-              prop
-              value
-              nil)))))
+            (let
+              ((raw-tgt (nth ast 4)))
+              (list
+                (quote hs-transition)
+                (if (nil? raw-tgt) (quote me) (hs-to-sx raw-tgt))
+                prop
+                value
+                (nth ast 3)))
+            (let
+              ((raw-tgt (nth ast 3)))
+              (list
+                (quote hs-transition)
+                (if (nil? raw-tgt) (quote me) (hs-to-sx raw-tgt))
+                prop
+                value
+                nil))))))
     (define
       emit-make
       (fn
@@ -913,6 +917,19 @@
                       (list (quote dom-set-style) tgt "visibility" "visible"))
                     (true (list (quote dom-set-style) tgt "display" "")))))
               ((= head (quote transition)) (emit-transition ast))
+              ((= head (quote transition-from))
+                (let
+                  ((prop (nth ast 1))
+                    (from-val (hs-to-sx (nth ast 2)))
+                    (to-val (hs-to-sx (nth ast 3)))
+                    (dur (nth ast 4)))
+                  (list
+                    (quote hs-transition-from)
+                    (quote me)
+                    prop
+                    from-val
+                    to-val
+                    dur)))
               ((= head (quote repeat)) (emit-repeat ast))
               ((= head (quote fetch))
                 (list (quote hs-fetch) (hs-to-sx (nth ast 1)) (nth ast 2)))