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()