feat(joinir): Phase 202-A Pattern 1 uses JoinValueSpace

Migrated Pattern 1 (Simple While) to use JoinValueSpace for unified
ValueId allocation, following the same pattern as Pattern 2 (Phase 201).

Changes:
- simple_while_minimal.rs: Added join_value_space parameter, replaced
  value_counter with join_value_space.alloc_local()
- pattern1_minimal.rs: Create JoinValueSpace before calling lowerer
- loop_view_builder.rs: Create JoinValueSpace in try_pattern1()

Pattern 1 uses Local region (1000+) only, since it doesn't need
ConditionEnv (no Param region allocation required).

Tested:
- cargo build --release --lib: Success (0 errors, 4 warnings)
- cargo test --release --lib pattern: 119 passed
- E2E test apps/tests/loop_min_while.hako: Outputs "0 1 2" correctly

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

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

src/mir/join_ir/lowering/loop_view_builder.rs

@@ -118,6 +118,8 @@ impl LoopViewBuilder {
     /// - 関数名に "main" が含まれる
     /// - Pinned vars がない
     /// - Carriers が1つ以上
+    ///
+    /// # Phase 202-A: JoinValueSpace Integration
     fn try_pattern1(&self, scope: &LoopScopeShape, name: &str) -> Option<JoinModule> {
         if !name.contains("main") {
             return None;
@@ -128,7 +130,14 @@ impl LoopViewBuilder {
                 eprintln!("[LoopViewBuilder] Trying Pattern 1 lowering for {:?}", name);
             }
 
-            if let Some(result) = super::simple_while_minimal::lower_simple_while_minimal(scope.clone()) {
+            // Phase 202-A: Create JoinValueSpace for Pattern 1
+            use super::join_value_space::JoinValueSpace;
+            let mut join_value_space = JoinValueSpace::new();
+
+            if let Some(result) = super::simple_while_minimal::lower_simple_while_minimal(
+                scope.clone(),
+                &mut join_value_space,
+            ) {
                 if self.debug {
                     eprintln!("[LoopViewBuilder] Pattern 1 lowering succeeded for {:?}", name);
                 }