Zero bootstrap patches: all 11 moved to spec or runtime

- make-raise-guard-frame: was never defined in spec — added it
- *last-error-kont*: set at error origination (host-error calls), not
  wrapped around every cek-run step. Zero overhead on normal path.
- JIT: jit-try-call runtime function called from spec. Platform
  registers hook via _jit_try_call_fn ref. No bootstrap patching.
- bootstrap.py compile_spec_to_ml() now returns transpiled output
  with zero post-processing.

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

spec/evaluator.sx

@@ -127,6 +127,8 @@
 
 (define make-raise-eval-frame (fn (env continuable?) {:scheme continuable? :env env :type "raise-eval"}))
 
+(define make-raise-guard-frame (fn (env saved-kont) {:env env :type "raise-guard" :remaining saved-kont}))
+
 (define
   find-matching-handler
   (fn
@@ -2640,8 +2642,10 @@
                   (handler-fn (kont-find-handler rest-k condition)))
                 (if
                   (nil? handler-fn)
-                  (host-error
-                    (str "Unhandled exception: " (inspect condition)))
+                  (do
+                    (set! *last-error-kont* rest-k)
+                    (host-error
+                      (str "Unhandled exception: " (inspect condition))))
                   (continue-with-call
                     handler-fn
                     (list condition)
@@ -2654,8 +2658,10 @@
                         rest-k)
                       (kont-push (make-raise-guard-frame fenv rest-k) rest-k))))))
             ("raise-guard"
-              (host-error
-                "exception handler returned from non-continuable raise"))
+              (do
+                (set! *last-error-kont* rest-k)
+                (host-error
+                  "exception handler returned from non-continuable raise")))
             ("multi-map"
               (let
                 ((f (get frame "f"))
@@ -2685,7 +2691,10 @@
                   (get frame "env")
                   (list k)
                   rest-k)))
-            (_ (error (str "Unknown frame type: " ft)))))))))
+            (_
+              (do
+                (set! *last-error-kont* rest-k)
+                (error (str "Unknown frame type: " ft))))))))))
 
 (define
   continue-with-call
@@ -2733,7 +2742,12 @@
           (for-each
             (fn (p) (env-bind! local p nil))
             (slice params (len args))))
-        (make-cek-state (lambda-body f) local kont))
+        (let
+          ((jit-result (jit-try-call f args)))
+          (if
+            (nil? jit-result)
+            (make-cek-state (lambda-body f) local kont)
+            (make-cek-value jit-result local kont))))
       (or (component? f) (island? f))
       (let
         ((parsed (parse-keyword-args raw-args env))