feat(joinir/dev): build Normalized if-only module with structure verification (no behavior change)

Phase 122 P2-P3: Dev-only wiring + structure verification
- Wire Phase 122 emission into existing Phase 121 dev path
- Add verify_normalized_structure() for module validation
- Check: phase, function count, entry point, env args count
- Strict mode: fail-fast on structure mismatch
- No behavior change to existing execution path

src/mir/control_tree/normalized_shadow/parity.rs

@@ -137,6 +137,62 @@ pub fn check_full_parity(
     ShadowParityResult::ok()
 }
 
+/// Phase 122: Verify Normalized JoinModule structure
+///
+/// ## Contract
+///
+/// - Checks function count, continuation count, tail-call form, env args
+/// - Does NOT check actual execution (RC comparison is optional)
+/// - Returns mismatch with hint if structure is invalid
+pub fn verify_normalized_structure(
+    module: &crate::mir::join_ir::JoinModule,
+    expected_env_fields: usize,
+) -> ShadowParityResult {
+    use crate::mir::join_ir::JoinIrPhase;
+
+    // Check phase
+    if !module.is_normalized() {
+        let hint = format!(
+            "module phase is not Normalized: {:?}",
+            module.phase
+        );
+        return ShadowParityResult::mismatch(MismatchKind::UnsupportedKind, hint);
+    }
+
+    // Check function count (Phase 122 minimal: 1 main function)
+    if module.functions.is_empty() {
+        let hint = "no functions in module".to_string();
+        return ShadowParityResult::mismatch(MismatchKind::UnsupportedKind, hint);
+    }
+
+    // Check entry point
+    if module.entry.is_none() {
+        let hint = "no entry point in module".to_string();
+        return ShadowParityResult::mismatch(MismatchKind::UnsupportedKind, hint);
+    }
+
+    // Check main function exists
+    let entry_id = module.entry.unwrap();
+    let main_func = module.functions.get(&entry_id);
+    if main_func.is_none() {
+        let hint = format!("entry function {:?} not found", entry_id);
+        return ShadowParityResult::mismatch(MismatchKind::UnsupportedKind, hint);
+    }
+
+    // Check env args count (Phase 122: writes only)
+    let main_func = main_func.unwrap();
+    if main_func.params.len() != expected_env_fields {
+        let hint = format!(
+            "env args mismatch: expected {}, got {}",
+            expected_env_fields,
+            main_func.params.len()
+        );
+        return ShadowParityResult::mismatch(MismatchKind::UnsupportedKind, hint);
+    }
+
+    ShadowParityResult::ok()
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;