feat(mir): Phase 25.1f完了 - Conservative PHI + ControlForm観測レイヤー

🎉 Conservative PHI Box理論による完全SSA構築

**Phase 7-B: Conservative PHI実装**
- 片方branchのみ定義変数に対応（emit_void使用）
- 全変数にPHI生成（Conservative Box理論）
- Stage-1 resolver全テスト緑化（3/3 PASS）

**Phase 25.1f: ControlForm観測レイヤー**
- LoopShape/IfShape/ControlForm構造定義
- Loop/If統一インターフェース実装
- debug_dump/debug_validate機能追加
- NYASH_CONTROL_FORM_TRACE環境変数対応

**主な変更**:
- src/mir/builder/phi.rs: Conservative PHI実装
- src/mir/control_form.rs: ControlForm構造（NEW）
- src/mir/loop_builder.rs: LoopForm v2デフォルト化

**テスト結果**:
✅ mir_stage1_using_resolver_min_fragment_verifies
✅ mir_stage1_using_resolver_full_collect_entries_verifies
✅ mir_parserbox_parse_program2_harness_parses_minimal_source

🤖 Generated with Claude Code
Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: ChatGPT <chatgpt@openai.com>

src/runner/modes/common_util/plugin_guard.rs

@@ -22,7 +22,7 @@ pub fn gather_required_providers() -> Vec<String> {
         return v;
     }
     // Default conservative set
-    let mut v = vec![
+    let v = vec![
         "FileBox".to_string(),
         "ConsoleBox".to_string(),
         "ArrayBox".to_string(),
@@ -86,4 +86,3 @@ pub fn check_and_report(strict: bool, quiet_pipe: bool, label: &str) {
         }
     }
 }
-

src/runner/modes/common_util/resolve/prelude_manager.rs

@@ -111,7 +111,7 @@ impl<'a> PreludeManagerBox<'a> {
     fn build_text_merged(
         &self,
         source: &str,
-        filename: &str,
+        _filename: &str,
         prelude_paths: &[String],
         trace: bool,
     ) -> Result<String, String> {
@@ -123,7 +123,7 @@ impl<'a> PreludeManagerBox<'a> {
                 .map_err(|e| format!("using: failed to read '{}': {}", path, e))?;
 
             // using行を除去して正規化
-            let using_resolver = UsingResolutionBox::new(&self.runner, path)?;
+            let _using_resolver = UsingResolutionBox::new(&self.runner, path)?;
             let (cleaned_raw, _nested) = self.collect_using_and_strip_internal(&content, path)?;
             let cleaned = self.normalize_text_for_inline(&cleaned_raw);
 

src/runner/modes/common_util/resolve/selfhost_pipeline.rs

@@ -129,7 +129,7 @@ impl<'a> SelfhostPipelineBox<'a> {
         &self,
         error: &str,
         original_code: &str,
-        filename: &str,
+        _filename: &str,
     ) -> CompilationResult {
         eprintln!("[selfhost-pipeline] ⚠️ Error: {}", error);
         eprintln!("[selfhost-pipeline] 🔄 Falling back to original code");
@@ -179,8 +179,8 @@ impl<'a> SelfhostPipelineBox<'a> {
     /// 📊 パフォーマンスプロファイリングするにゃ！
     pub fn profile_pipeline(
         &mut self,
-        code: &str,
-        filename: &str,
+        _code: &str,
+        _filename: &str,
     ) -> Result<String, String> {
         // プロファイル機能を実装（別途）
         // TODO: プロファイル機能を追加

src/runner/modes/common_util/resolve/strip.rs

@@ -448,7 +448,7 @@ pub fn resolve_prelude_paths_profiled(
     // must be discovered so that their definitions are present at runtime
     // (e.g., runner_min -> lower_* boxes). Previously this only ran when
     // NYASH_USING_AST=1, which caused unresolved calls in inline flows.
-    let ast_on = crate::config::env::env_bool("NYASH_USING_AST");
+    let _ast_on = crate::config::env::env_bool("NYASH_USING_AST");
     let mut out: Vec<String> = Vec::new();
     let mut seen: std::collections::HashSet<String> = std::collections::HashSet::new();
     fn normalize_path(path: &str) -> (String, String) {

src/runner/modes/common_util/resolve/using_resolution.rs

@@ -14,6 +14,7 @@ pub struct UsingResolutionBox<'a> {
     runner: &'a NyashRunner,
     config: UsingConfig,
     ctx_dir: Option<PathBuf>,
+    #[allow(dead_code)]
     filename_canon: Option<PathBuf>,
     inside_pkg: bool,
     seen_paths: HashMap<String, (String, usize)>, // canon_path -> (alias/label, first_line)

src/runner/modes/vm.rs

@@ -476,7 +476,7 @@ impl NyashRunner {
 
         match vm.execute_module(&module_vm) {
             Ok(ret) => {
-                use crate::box_trait::{NyashBox, IntegerBox, BoolBox};
+                use crate::box_trait::{IntegerBox, BoolBox};
 
                 // Extract exit code from return value
                 let exit_code = if let Some(ib) = ret.as_any().downcast_ref::<IntegerBox>() {

src/runner/modes/vm_fallback.rs

@@ -321,7 +321,7 @@ impl NyashRunner {
         }
         match vm.execute_module(&module_vm) {
             Ok(ret) => {
-                use crate::box_trait::{NyashBox, IntegerBox, BoolBox};
+                use crate::box_trait::{IntegerBox, BoolBox};
 
                 // Extract exit code from return value
                 let exit_code = if let Some(ib) = ret.as_any().downcast_ref::<IntegerBox>() {
@@ -346,7 +346,8 @@ impl NyashRunner {
 
 impl NyashRunner {
     /// Small helper to continue fallback execution once AST is prepared
-    fn execute_vm_fallback_from_ast(&self, filename: &str, ast: nyash_rust::ast::ASTNode) {
+    #[allow(dead_code)]
+    fn execute_vm_fallback_from_ast(&self, _filename: &str, ast: nyash_rust::ast::ASTNode) {
         use crate::{
             backend::MirInterpreter,
             box_factory::{BoxFactory, RuntimeError},