vm-ext: fix common-lisp condition-system JIT residual (call/cc-caller exclusion)

The 6 common-lisp opt-in-JIT failures were all condition-system continuation
escape: cl-restart-case/cl-handler-case/cl-handler-bind wrap their body in
call/cc (restarts + non-local handler exit). When an SX function that drives
the condition system (the parse-recover / interactive-debugger fixtures, e.g.
parse-numbers, make-policy-debugger) is JIT-compiled, the call/cc form runs in
a NESTED cek-run where invoking the captured continuation
runs-to-completion-and-returns instead of escaping — so a restart fails to
abort and the body falls through. Observed as result accumulation
(got (1 3 0 3) vs (1 3)) and no-abort (restart returns the 999 sentinel).

These callers are arbitrary user/fixture code, not a fixed namespace, so they
can't be prefix-excluded. New data-driven mechanism:
- jit-exclude-callers-of! registers call/cc-establishing form names in
  Sx_types.jit_excluded_caller_names.
- jit_compile_lambda skips any function whose constant pool (recursively,
  incl. nested closures) references a registered name — code_refs_escaping_caller.
  Guarded by Hashtbl.length > 0 so it's a no-op for every guest that doesn't
  register (zero effect outside CL).
- lib/common-lisp/runtime.sx registers the establish side (cl-restart-case,
  cl-handler-case, cl-handler-bind) and the invoke side (cl-invoke-restart,
  cl-invoke-debugger, cl-signal, cl-error-with-debugger).

Result: CL conformance under SX_SERVING_JIT=1 = 487/0, EXACTLY matching the CEK
baseline (was 484/6 with a +3 double-execution over-count). parse-recover
3/4 -> 6/0, interactive-debugger 7/2 -> 7/0.

Note: the geometry/mop-trace suites report 0/0 on BOTH CEK and JIT — they error
"Undefined symbol: refl-class-chain-depth-with" (the CLOS suites don't preload
lib/guest/reflective/class-chain.sx). Pre-existing conformance-harness gap, not
a JIT issue; left as-is.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

hosts/ocaml/lib/sx_primitives.ml

@@ -4175,6 +4175,16 @@ let () =
     match args with
     | [String n] | [Symbol n] -> Bool (Sx_types.jit_name_excluded n)
     | _ -> Bool false);
+  register "jit-exclude-callers-of!" (fun args ->
+    (* Register call/cc-establishing forms (e.g. cl-restart-case). Any function
+       whose bytecode references one of these is itself interpret-only — JIT
+       would force the form into a nested cek-run where its continuation can't
+       escape. A guest declares its condition-system / escaping forms here. *)
+    List.iter (fun a ->
+      match a with
+      | String n | Symbol n -> Hashtbl.replace Sx_types.jit_excluded_caller_names n ()
+      | _ -> ()) args;
+    Nil);
   register "jit-reset-counters!" (fun _args ->
     Sx_types.jit_compiled_count := 0;
     Sx_types.jit_skipped_count := 0;