Step 10d: bytecode expansion — close the CEK gap

Tier 1 — Component keyword dispatch on VM:
- Components/islands JIT-compile bodies via jit_compile_comp
- parse_keyword_args matches keyword names against component params
- Added i_compiled field to island type for JIT cache
- Component calls no longer fall back to CEK

Tier 2 — OP_SWAP (opcode 7):
- New stack swap operation for future HO loop compilation
- HO forms already efficient via NativeFn + VmClosure callbacks

Tier 3 — Exception handler stack:
- OP_PUSH_HANDLER (35), OP_POP_HANDLER (36), OP_RAISE (37)
- VM gains handler_stack with frame depth tracking
- Compiler handles guard and raise as bytecode
- Functions with exception handling no longer cause JIT failure

Tier 4 — Scope forms as bytecode:
- Compiler handles provide, context, peek, scope, provide!,
  bind, emit!, emitted via CALL_PRIM sequences
- Functions using reactive scope no longer trigger JIT failure

4 new opcodes (SWAP, PUSH_HANDLER, POP_HANDLER, RAISE) → 37 total.
2776/2776 tests pass, zero regressions.

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

hosts/ocaml/bin/run_tests.ml

@@ -614,7 +614,7 @@ let make_test_env () =
       let island = Island {
         i_name = short_name; i_params = param_names;
         i_has_children = has_children;
-        i_body = body; i_closure = eval_env; i_file = None;
+        i_body = body; i_closure = eval_env; i_file = None; i_compiled = None;
       } in
       ignore (Sx_types.env_bind eval_env name island);
       island