feat(joinir): Phase 131-11 A-C - InfiniteEarlyExit パターン追加（検出部分）

## Step A: Feature Detection
- LoopPatternKind::InfiniteEarlyExit (Pattern 5) 追加
- LoopFeatures::is_infinite_loop フィールド追加
- detect_infinite_loop() で loop(true) 検出

## Step B: Classification Logic
- classify() を更新: Pattern 5 を Pattern 4 より優先
- Pattern 4 を狭化: has_continue && !has_break のみ
- 誤ルーティング完全除去

## Step C: Pattern Module
- pattern5_infinite_early_exit.rs 新規作成
- Fail-Fast 設計: 超狭い shape guard
- lowering はスケルトン（Phase 131-11-D で実装）

## 動作確認
- Pattern 5 正常検出 ✅
- Shape guards 動作（1 break, 1 continue, 1 carrier）✅
- Pattern 4 誤ルーティング回避 ✅

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/mir/builder/control_flow/joinir/patterns/router.rs

@@ -69,6 +69,7 @@ impl<'a> LoopPatternContext<'a> {
     /// Phase 194+: Automatically detects continue/break statements in body
     /// Phase 192: Extract features and classify pattern from AST
     /// Phase 193: Feature extraction delegated to ast_feature_extractor module
+    /// Phase 131-11: Detects infinite loop condition
     pub(crate) fn new(
         condition: &'a ASTNode,
         body: &'a [ASTNode],
@@ -80,7 +81,8 @@ impl<'a> LoopPatternContext<'a> {
         let has_break = ast_features::detect_break_in_body(body);
 
         // Phase 193: Extract features using modularized extractor
-        let features = ast_features::extract_features(body, has_continue, has_break);
+        // Phase 131-11: Pass condition for infinite loop detection
+        let features = ast_features::extract_features(condition, body, has_continue, has_break);
 
         // Phase 192: Classify pattern based on features
         let pattern_kind = crate::mir::loop_pattern_detection::classify(&features);
@@ -135,10 +137,14 @@ pub(crate) struct LoopPatternEntry {
 /// Static table of all registered loop patterns.
 /// Patterns are tried in priority order (lowest first).
 ///
-/// # Current Patterns (Phase 192: Structure-based detection)
+/// # Current Patterns (Phase 131-11: Pattern 5 added)
 ///
 /// All patterns now use structure-based detection via LoopFeatures and classify():
 ///
+/// - Pattern 5 (priority 1): Infinite Loop with Early Exit (llvm_stage3_loop_only.hako) [Phase 131-11]
+///   - Detection: pattern_kind == InfiniteEarlyExit
+///   - Structure: is_infinite_loop && has_break && has_continue
+///
 /// - Pattern 4 (priority 5): Loop with Continue (loop_continue_pattern4.hako)
 ///   - Detection: pattern_kind == Pattern4Continue
 ///   - Structure: has_continue && !has_break
@@ -157,9 +163,15 @@ pub(crate) struct LoopPatternEntry {
 ///
 /// Note: func_name is now only used for debug logging, not pattern detection
 pub(crate) static LOOP_PATTERNS: &[LoopPatternEntry] = &[
+    LoopPatternEntry {
+        name: "Pattern5_InfiniteEarlyExit",
+        priority: 1, // Highest priority - most specific (infinite loop with break+continue)
+        detect: super::pattern5_infinite_early_exit::can_lower,
+        lower: super::pattern5_infinite_early_exit::lower,
+    },
     LoopPatternEntry {
         name: "Pattern4_WithContinue",
-        priority: 5, // Highest priority - continue is most specific
+        priority: 5, // Second priority - continue without break
         detect: super::pattern4_with_continue::can_lower,
         lower: super::pattern4_with_continue::lower,
     },