refactor(runner): Phase 105.5 Console出力のmacro統一化

- Replace direct console.println() calls with console_println! macro
- Simplify error handling in vm.rs (RC output)
- Simplify success logging in selfhost.rs (PluginHost init)
- Remove redundant nested if-let structures for Option handling
- Macro already handles all fallback scenarios (eprintln!)

This reduces code duplication and improves consistency. The macro
centralizes the fallback logic, making it easier to maintain.

Files modified:
- src/runner/modes/vm.rs (simplified RC output)
- src/runner/selfhost.rs (simplified PluginHost init message)

Line reduction: ~13 lines (nested if-let structures removed)

src/runner/modes/vm.rs

@@ -586,17 +586,8 @@ impl NyashRunner {
 
                 // Quiet mode: suppress "RC:" output for JSON-only pipelines
                 if !quiet_pipe {
-                    // Phase 98: ConsoleService if available, otherwise eprintln
-                    // Phase 103: Handle Option<Arc<dyn ConsoleService>>
-                    if let Some(host) = crate::runtime::try_get_core_plugin_host() {
-                        if let Some(ref console) = host.core.console {
-                            console.println(&format!("RC: {}", exit_code));
-                        } else {
-                            println!("RC: {}", exit_code);
-                        }
-                    } else {
-                        println!("RC: {}", exit_code);
-                    }
+                    // Phase 105.5: Unified console output via macro
+                    crate::console_println!("RC: {}", exit_code);
                 }
                 if std::env::var("NYASH_EMIT_MIR_TRACE")
                     .ok()

src/runner/selfhost.rs

@@ -48,15 +48,11 @@ impl NyashRunner {
             let ring0 = crate::runtime::ring0::get_global_ring0();
             match crate::runtime::initialize_runtime(ring0) {
                 Ok(()) => {
-                    // Phase 95: ConsoleService 経由でログ出力（代表パス）
-                    // Phase 103: Handle Option<Arc<dyn ConsoleService>>
-                    let host = crate::runtime::get_core_plugin_host();
-                    if let Some(ref console) = host.core.console {
-                        console.println("[selfhost] PluginHost initialized successfully");
-                    }
+                    // Phase 105.5: Unified console output via macro
+                    crate::console_println!("[selfhost] PluginHost initialized successfully");
                 }
                 Err(e) => {
-                    // Phase 100: ConsoleService 経由でエラー出力
+                    // Phase 105.5: Unified console output via macro
                     crate::console_println!("[selfhost] CoreInitError: {}", e);
                     return false;
                 }