feat: nyash.toml SSOT + using AST統合完了（12時間の戦い）

- nyash.tomlを唯一の真実（SSOT）として依存管理確立
- dev/ci/prodプロファイルによる段階的厳格化実装
- AST結合で宣言/式の曖昧性を根本解決
- Fail-Fast原則をCLAUDE.md/AGENTS.mdに明文化
- VM fallbackでもASTベース using有効化（NYASH_USING_AST=1）
- 静的メソッドの is_static=true 修正で解決安定化
- STATICブレークハック既定OFF化で堅牢性向上

🎉 usingシステム完全体への道筋確立！JSONライブラリ・Nyash VM開発が可能に

Co-Authored-By: Claude <noreply@anthropic.com>

src/runner/modes/vm_fallback.rs

@@ -12,23 +12,79 @@ impl NyashRunner {
             Ok(s) => s,
             Err(e) => { eprintln!("❌ Error reading file {}: {}", filename, e); process::exit(1); }
         };
-        // Using preprocessing (strip + autoload)
+        // Using preprocessing (legacy inline or AST-prelude merge when NYASH_USING_AST=1)
         let mut code2 = code;
+        let use_ast_prelude = crate::config::env::enable_using()
+            && std::env::var("NYASH_USING_AST").ok().as_deref() == Some("1");
+        let mut prelude_asts: Vec<nyash_rust::ast::ASTNode> = Vec::new();
         if crate::config::env::enable_using() {
-            match crate::runner::modes::common_util::resolve::strip_using_and_register(self, &code2, filename) {
-                Ok(s) => { code2 = s; }
-                Err(e) => { eprintln!("❌ {}", e); process::exit(1); }
+            if use_ast_prelude {
+                match crate::runner::modes::common_util::resolve::resolve_prelude_paths_profiled(self, &code2, filename) {
+                    Ok((clean, paths)) => {
+                        code2 = clean;
+                        for p in paths {
+                            match std::fs::read_to_string(&p) {
+                                Ok(src) => match NyashParser::parse_from_string(&src) {
+                                    Ok(ast) => prelude_asts.push(ast),
+                                    Err(e) => { eprintln!("❌ Parse error in using prelude {}: {}", p, e); process::exit(1); }
+                                },
+                                Err(e) => { eprintln!("❌ Error reading using prelude {}: {}", p, e); process::exit(1); }
+                            }
+                        }
+                    }
+                    Err(e) => { eprintln!("❌ {}", e); process::exit(1); }
+                }
+            } else {
+                match crate::runner::modes::common_util::resolve::strip_using_and_register(self, &code2, filename) {
+                    Ok(s) => { code2 = s; }
+                    Err(e) => { eprintln!("❌ {}", e); process::exit(1); }
+                }
             }
         }
         // Dev sugar pre-expand: @name = expr → local name = expr
         code2 = crate::runner::modes::common_util::resolve::preexpand_at_local(&code2);
 
-        // Parse -> expand macros -> compile MIR
-        let ast = match NyashParser::parse_from_string(&code2) {
+        // Parse main code
+        let main_ast = match NyashParser::parse_from_string(&code2) {
             Ok(ast) => ast,
             Err(e) => { eprintln!("❌ Parse error: {}", e); process::exit(1); }
         };
-        let ast = crate::r#macro::maybe_expand_and_dump(&ast, false);
+        // When using AST prelude mode, combine prelude ASTs + main AST into one Program before macro expansion
+        let ast_combined = if use_ast_prelude && !prelude_asts.is_empty() {
+            use nyash_rust::ast::ASTNode;
+            let mut combined: Vec<ASTNode> = Vec::new();
+            for a in prelude_asts {
+                if let ASTNode::Program { statements, .. } = a { combined.extend(statements); }
+            }
+            if let ASTNode::Program { statements, .. } = main_ast.clone() {
+                combined.extend(statements);
+            }
+            ASTNode::Program { statements: combined, span: nyash_rust::ast::Span::unknown() }
+        } else { main_ast };
+        // Optional: dump AST statement kinds for quick diagnostics
+        if std::env::var("NYASH_AST_DUMP").ok().as_deref() == Some("1") {
+            use nyash_rust::ast::ASTNode;
+            eprintln!("[ast] dump start (vm-fallback)");
+            if let ASTNode::Program { statements, .. } = &ast_combined {
+                for (i, st) in statements.iter().enumerate().take(50) {
+                    let kind = match st {
+                        ASTNode::BoxDeclaration { is_static, name, .. } => {
+                            if *is_static { format!("StaticBox({})", name) } else { format!("Box({})", name) }
+                        }
+                        ASTNode::FunctionDeclaration { name, .. } => format!("FuncDecl({})", name),
+                        ASTNode::FunctionCall { name, .. } => format!("FuncCall({})", name),
+                        ASTNode::MethodCall { method, .. } => format!("MethodCall({})", method),
+                        ASTNode::ScopeBox { .. } => "ScopeBox".to_string(),
+                        ASTNode::ImportStatement { path, .. } => format!("Import({})", path),
+                        ASTNode::UsingStatement { namespace_name, .. } => format!("Using({})", namespace_name),
+                        _ => format!("{:?}", st),
+                    };
+                    eprintln!("[ast] {}: {}", i, kind);
+                }
+            }
+            eprintln!("[ast] dump end");
+        }
+        let ast = crate::r#macro::maybe_expand_and_dump(&ast_combined, false);
         let mut compiler = MirCompiler::with_options(!self.config.no_optimize);
         let compile = match compiler.compile(ast) {
             Ok(c) => c,
@@ -44,6 +100,12 @@ impl NyashRunner {
 
         // Execute via MIR interpreter
         let mut vm = MirInterpreter::new();
+        if std::env::var("NYASH_DUMP_FUNCS").ok().as_deref() == Some("1") {
+            eprintln!("[vm] functions available:");
+            for k in module_vm.functions.keys() {
+                eprintln!("  - {}", k);
+            }
+        }
         match vm.execute_module(&module_vm) {
             Ok(_ret) => { /* interpreter already prints via println/console in program */ }
             Err(e) => {