fix: Complete JIT/Cranelift archival cleanup for Phase 15

- Create JIT stub module with minimal compatibility layer
- Archive JIT-direct execution mode with helpful error message
- Fix remaining JIT references in config, runtime, and backend modules
- Resolve compilation errors preventing Phase 15 development
- All JIT functionality now properly archived to archive/jit-cranelift/

🎯 Phase 15 compilation now succeeds - ready for selfhosting debug

🤖 Generated with [Claude Code](https://claude.ai/code)

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

src/runner/json_v0_bridge/lowering/expr.rs

@@ -232,11 +232,12 @@ pub(super) fn lower_expr_with_scope<S: VarScope>(
                     });
                 }
             }
-            crate::jit::events::emit_lower(
-                serde_json::json!({ "id":"shortcircuit","op": if is_and {"and"} else {"or"},"rhs_bb":rhs_bb.0,"fall_bb":fall_bb.0,"merge_bb":merge_bb.0 }),
-                "shortcircuit",
-                "<json_v0>",
-            );
+            // ARCHIVED: JIT events moved to archive/jit-cranelift/ during Phase 15
+            // crate::jit::events::emit_lower(
+            //     serde_json::json!({ "id":"shortcircuit","op": if is_and {"and"} else {"or"},"rhs_bb":rhs_bb.0,"fall_bb":fall_bb.0,"merge_bb":merge_bb.0 }),
+            //     "shortcircuit",
+            //     "<json_v0>",
+            // );
             let cdst = f.next_value_id();
             if let Some(bb) = f.get_block_mut(fall_bb) {
                 let cval = if is_and {