feat: 改行処理革命Phase 2-B完了 - Box宣言系skip_newlines()完全削除

✅ **41%削減達成**: 48→35→21箇所（14箇所削除）
- fields.rs: 9箇所のskip_newlines()削除
- box_definition.rs: 3箇所削除
- static_box.rs: 2箇所削除

✅ **Smart advance()実用化**: 深度追跡で自動改行処理完璧機能
- Box宣言、match式OR、複数行構文すべて対応
- NYASH_SMART_ADVANCE=1で安定動作確認

🔧 **ORパターンバグ同時修正**: exprs_peek.rsでInteger/Boolean型マッチング実装
- 修正前: 1 | 2 => "found" が動作せず（String型のみ）
- 修正後: 全リテラル型（Integer/Bool/Float/Null/Void）完全対応

🎉 **技術的価値**: 手動skip依存→コンテキスト認識自動処理への移行成功

🤖 Generated with [Claude Code](https://claude.ai/code)

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

src/parser/declarations/box_def/members/fields.rs

@@ -40,7 +40,6 @@ pub(crate) fn try_parse_header_first_field_or_property(
             p.advance();
             let _init_expr = p.parse_expression()?; // P0: parse and discard
             fields.push(fname);
-            p.skip_newlines();
             return Ok(true);
         }
         // name: Type => expr  → computed property (getter method with return expr)
@@ -61,7 +60,6 @@ pub(crate) fn try_parse_header_first_field_or_property(
                 span: Span::unknown(),
             };
             methods.insert(getter_name, method);
-            p.skip_newlines();
             return Ok(true);
         }
         // name: Type { ... } [postfix]
@@ -78,7 +76,6 @@ pub(crate) fn try_parse_header_first_field_or_property(
                 span: Span::unknown(),
             };
             methods.insert(getter_name, method);
-            p.skip_newlines();
             return Ok(true);
         }
     }
@@ -108,7 +105,6 @@ pub(crate) fn try_parse_visibility_block_or_single(
     }
     if p.match_token(&TokenType::LBRACE) {
         p.advance();
-        p.skip_newlines();
         while !p.match_token(&TokenType::RBRACE) && !p.is_at_end() {
             if let TokenType::IDENTIFIER(fname) = &p.current_token().token_type {
                 let fname = fname.clone();
@@ -116,7 +112,6 @@ pub(crate) fn try_parse_visibility_block_or_single(
                 fields.push(fname);
                 p.advance();
                 if p.match_token(&TokenType::COMMA) { p.advance(); }
-                p.skip_newlines();
                 continue;
             }
             return Err(ParseError::UnexpectedToken {
@@ -126,7 +121,6 @@ pub(crate) fn try_parse_visibility_block_or_single(
             });
         }
         p.consume(TokenType::RBRACE)?;
-        p.skip_newlines();
         return Ok(true);
     }
     if let TokenType::IDENTIFIER(n) = &p.current_token().token_type {
@@ -135,12 +129,10 @@ pub(crate) fn try_parse_visibility_block_or_single(
         if try_parse_header_first_field_or_property(p, fname.clone(), methods, fields)? {
             if visibility == "public" { public_fields.push(fname.clone()); } else { private_fields.push(fname.clone()); }
             *last_method_name = None;
-            p.skip_newlines();
             return Ok(true);
         } else {
             if visibility == "public" { public_fields.push(fname.clone()); } else { private_fields.push(fname.clone()); }
             fields.push(fname);
-            p.skip_newlines();
             return Ok(true);
         }
     }
@@ -160,7 +152,6 @@ pub(crate) fn parse_init_block_if_any(
     p.advance(); // consume 'init'
     p.consume(TokenType::LBRACE)?;
     while !p.match_token(&TokenType::RBRACE) && !p.is_at_end() {
-        p.skip_newlines();
         if p.match_token(&TokenType::RBRACE) {
             break;
         }

src/parser/declarations/box_definition.rs

@@ -116,7 +116,6 @@ impl NyashParser {
             box_header::parse_header(self)?;
 
         self.consume(TokenType::LBRACE)?;
-        self.skip_newlines(); // ブレース後の改行をスキップ
 
         let mut fields = Vec::new();
         let mut methods = HashMap::new();
@@ -130,7 +129,6 @@ impl NyashParser {
 
         let mut last_method_name: Option<String> = None;
         while !self.match_token(&TokenType::RBRACE) && !self.is_at_end() {
-            self.skip_newlines(); // ループ開始時に改行をスキップ
             // 分類（段階移行用の観測）: 将来の分岐移譲のための前処理
             if crate::config::env::parser_stage3() {
                 if let Ok(kind) = crate::parser::declarations::box_def::members::common::classify_member(self) {
@@ -189,7 +187,6 @@ impl NyashParser {
                         &mut birth_once_props,
                     )? {
                         last_method_name = None; // do not attach method-level postfix here
-                        self.skip_newlines();
                         continue;
                     }
                 }

src/parser/declarations/static_box.rs

@@ -18,7 +18,6 @@ impl NyashParser {
             crate::parser::declarations::static_def::header::parse_static_header(self)?;
 
         self.consume(TokenType::LBRACE)?;
-        self.skip_newlines(); // ブレース後の改行をスキップ
 
         let mut fields = Vec::new();
         let mut methods = HashMap::new();
@@ -30,7 +29,6 @@ impl NyashParser {
         // Track last inserted method name to allow postfix catch/cleanup fallback parsing
         let mut last_method_name: Option<String> = None;
         while !self.match_token(&TokenType::RBRACE) && !self.is_at_end() {
-            self.skip_newlines(); // ループ開始時に改行をスキップ
 
             // Fallback: method-level postfix catch/cleanup immediately following a method
             if crate::parser::declarations::box_def::members::postfix::try_parse_method_postfix_after_last_method(