feat(runtime): Phase 103 CoreServices Optional化 - Memory Constraints対応

- Add CoreServicesConfig struct (from_env, minimal, all_enabled)
- Implement with_core_from_registry_optional() for selective initialization
- Update CoreBoxesImpl fields to Option<Arc<dyn XyzService>>
- Maintain backward compatibility (with_core_from_registry calls all_enabled)
- Add NYASH_CORE_DISABLE_* environment variable support
- ConsoleBox remains mandatory (Graceful Degradation principle)
- Add unit tests for optional initialization
- Update console_println! macro to handle Option type
- Fix direct console.println() calls in vm.rs and selfhost.rs
- Create core_optional_design.md documentation

Note: Phase 104 will extend ConsoleService to be optional as well with
graceful fallback in console_println! macro.

Files modified:
- src/runtime/plugin_host.rs (CoreServicesConfig, with_core_from_registry_optional, tests)
- src/runtime/core_services.rs (CoreBoxesImpl fields → Option type)
- src/runtime/mod.rs (console_println! macro updated)
- src/runner/modes/vm.rs (handle Option console)
- src/runner/selfhost.rs (handle Option console)
- docs/development/current/main/core_optional_design.md (new)
- docs/development/current/main/ring0-inventory.md (Phase 103 entry)

Test results:
- Build: ✅ Success (0 errors, 7 warnings)
- Unit tests: ✅ 3/3 passed (optional_core_tests)
- Runtime tests: ✅ 63/63 passed
- Smoke tests: ✅ 30/31 passed (1 pre-existing timeout)

src/mir/join_ir_vm_bridge_dispatch/exec_routes.rs

@@ -1,9 +1,10 @@
+use crate::config::env::{joinir_dev_enabled, joinir_strict_enabled};
 use crate::mir::join_ir::{lower_funcscanner_trim_to_joinir, lower_skip_ws_to_joinir, JoinFuncId};
 use crate::mir::join_ir_ops::JoinValue;
 use crate::mir::join_ir_vm_bridge::run_joinir_via_vm;
 use crate::mir::MirModule;
+use crate::runtime::get_global_ring0;
 use std::process;
-use crate::config::env::{joinir_dev_enabled, joinir_strict_enabled};
 
 /// Main.skip/1 用 JoinIR ブリッジ（Exec: JoinIR→VM 実行まで対応）
 ///
@@ -155,14 +156,18 @@ where
     G: Fn(&JoinValue) -> String,
     H: Fn(&JoinValue) -> i32,
 {
-    eprintln!("[joinir/vm_bridge] Attempting JoinIR path for {}", route_name);
+    get_global_ring0()
+        .log
+        .info(&format!("[joinir/vm_bridge] Attempting JoinIR path for {}", route_name));
 
     let Some(join_module) = lowerer() else {
-        eprintln!(
+        get_global_ring0().log.info(&format!(
             "[joinir/vm_bridge] lower_{} returned None",
             route_name.replace(".", "_").to_lowercase()
-        );
-        eprintln!("[joinir/vm_bridge] Falling back to normal VM path");
+        ));
+        get_global_ring0()
+            .log
+            .info("[joinir/vm_bridge] Falling back to normal VM path");
         return false;
     };
 
@@ -172,7 +177,9 @@ where
 
     match run_joinir_via_vm(&join_module, JoinFuncId::new(0), &[input_val]) {
         Ok(result) => {
-            eprintln!("[joinir/vm_bridge] ✅ JoinIR result: {:?}", result);
+            get_global_ring0()
+                .log
+                .info(&format!("[joinir/vm_bridge] ✅ JoinIR result: {:?}", result));
             let output = output_formatter(&result);
             let exit_code = exit_code_extractor(&result);
 
@@ -194,11 +201,12 @@ where
             }
         }
         Err(e) => {
-            eprintln!(
-                "[joinir/vm_bridge] ❌ JoinIR {} failed: {:?}",
-                route_name, e
-            );
-            eprintln!("[joinir/vm_bridge] Falling back to normal VM path");
+            get_global_ring0()
+                .log
+                .info(&format!("[joinir/vm_bridge] ❌ JoinIR {} failed: {:?}", route_name, e));
+            get_global_ring0()
+                .log
+                .info("[joinir/vm_bridge] Falling back to normal VM path");
             false
         }
     }