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/printer.rs

@@ -7,6 +7,7 @@
 use super::printer_helpers;
 use super::{BasicBlock, MirFunction, MirInstruction, MirModule, MirType, ValueId};
 use crate::debug::log as dlog;
+use crate::runtime::get_global_ring0;
 use std::collections::BTreeMap;
 use std::fmt::Write;
 
@@ -162,12 +163,18 @@ impl MirPrinter {
                     match sp.inst {
                         MirInstruction::Throw { .. } => {
                             if dlog::on("NYASH_DEBUG_MIR_PRINTER") {
-                                eprintln!("[PRINTER] found throw in {}", function.signature.name);
+                                get_global_ring0().log.debug(&format!(
+                                    "[PRINTER] found throw in {}",
+                                    function.signature.name
+                                ));
                             }
                         }
                         MirInstruction::Catch { .. } => {
                             if dlog::on("NYASH_DEBUG_MIR_PRINTER") {
-                                eprintln!("[PRINTER] found catch in {}", function.signature.name);
+                                get_global_ring0().log.debug(&format!(
+                                    "[PRINTER] found catch in {}",
+                                    function.signature.name
+                                ));
                             }
                         }
                         MirInstruction::TypeCheck { .. } => type_check += 1,
@@ -195,18 +202,18 @@ impl MirPrinter {
                     match sp.inst {
                         MirInstruction::Throw { .. } => {
                             if dlog::on("NYASH_DEBUG_MIR_PRINTER") {
-                                eprintln!(
+                                get_global_ring0().log.debug(&format!(
                                     "[PRINTER] found throw(term) in {}",
                                     function.signature.name
-                                );
+                                ));
                             }
                         }
                         MirInstruction::Catch { .. } => {
                             if dlog::on("NYASH_DEBUG_MIR_PRINTER") {
-                                eprintln!(
+                                get_global_ring0().log.debug(&format!(
                                     "[PRINTER] found catch(term) in {}",
                                     function.signature.name
-                                );
+                                ));
                             }
                         }
                         MirInstruction::TypeCheck { .. } => type_check += 1,