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/runtime/plugin_loader_v2/enabled/ffi_bridge.rs

@@ -3,6 +3,7 @@
 use crate::bid::{BidError, BidResult};
 use crate::box_trait::NyashBox;
 use crate::runtime::plugin_loader_v2::enabled::PluginLoaderV2;
+use crate::runtime::get_global_ring0;
 use std::env;
 use std::sync::Arc;
 
@@ -27,10 +28,10 @@ impl PluginLoaderV2 {
             Ok(mid) => mid,
             Err(e) => {
                 if dbg_on() {
-                    eprintln!(
+                    get_global_ring0().log.debug(&format!(
                         "[PluginLoaderV2] ERR: method resolve failed for {}.{}: {:?}",
                         box_type, method_name, e
-                    );
+                    ));
                 }
                 return Err(BidError::InvalidMethod);
             }
@@ -43,7 +44,9 @@ impl PluginLoaderV2 {
         // Optional C wrapper (Phase 22.2: design insertion point; default OFF)
         if env::var("HAKO_PLUGIN_LOADER_C_WRAP").ok().as_deref() == Some("1") {
             if should_trace_cwrap(box_type, method_name) {
-                eprintln!("[cwrap:invoke:{}.{}]", box_type, method_name);
+                get_global_ring0()
+                    .log
+                    .debug(&format!("[cwrap:invoke:{}.{}]", box_type, method_name));
             }
             // Future: route into a thin C shim here. For now, fall through to normal path.
         }
@@ -52,7 +55,9 @@ impl PluginLoaderV2 {
         if env::var("HAKO_C_CORE_ENABLE").ok().as_deref() == Some("1")
             && should_route_ccore(box_type, method_name)
         {
-            eprintln!("[c-core:invoke:{}.{}]", box_type, method_name);
+            get_global_ring0()
+                .log
+                .debug(&format!("[c-core:invoke:{}.{}]", box_type, method_name));
             #[cfg(feature = "c-core")]
             {
                 // MapBox.set: call C-core stub (no-op) with available info
@@ -89,7 +94,9 @@ impl PluginLoaderV2 {
         // Unified call trace (optional): plugin calls
         if env::var("HAKO_CALL_TRACE").ok().as_deref() == Some("1") {
             if should_trace_call(box_type, method_name) {
-                eprintln!("[call:{}.{}]", box_type, method_name);
+                get_global_ring0()
+                    .log
+                    .debug(&format!("[call:{}.{}]", box_type, method_name));
             }
         }
 
@@ -98,18 +105,22 @@ impl PluginLoaderV2 {
             && env::var("HAKO_TLV_SHIM").ok().as_deref() == Some("1")
         {
             if should_trace_tlv_shim(box_type, method_name) {
-                eprintln!("[tlv/shim:{}.{}]", box_type, method_name);
+                get_global_ring0()
+                    .log
+                    .debug(&format!("[tlv/shim:{}.{}]", box_type, method_name));
                 if env::var("HAKO_TLV_SHIM_TRACE_DETAIL").ok().as_deref() == Some("1") {
-                    eprintln!("[tlv/shim:detail argc={}]", args.len());
+                    get_global_ring0()
+                        .log
+                        .debug(&format!("[tlv/shim:detail argc={}]", args.len()));
                 }
             }
         }
 
         if dbg_on() {
-            eprintln!(
+            get_global_ring0().log.debug(&format!(
                 "[PluginLoaderV2] call {}.{}: type_id={} method_id={} instance_id={}",
                 box_type, method_name, type_id, method_id, instance_id
-            );
+            ));
         }
 
         let (_code, out_len, out) = super::host_bridge::invoke_alloc(