feat(joinir): Phase 80-B/C/D - Pattern3/4 BindingId wiring + E2E tests (dev-only)

Task 80-B (P1): Pattern3 (if-sum) BindingId registration
- pattern3_with_if_phi.rs: Added BindingId→ValueId registration
- Loop var + condition bindings registration (lines 131-159)
- Debug logs: [phase80/p3] tags
- Follows Pattern2 template structure

Task 80-C (P2): Pattern4 (continue) BindingId registration
- pattern4_with_continue.rs: Pass binding_map to lowerer (lines 341-352)
- loop_with_continue_minimal.rs: Added BindingId→ValueId registration (lines 206-230)
- Loop var + condition bindings registration
- Debug logs: [phase80/p4] tags
- Follows Pattern2 template structure

Task 80-D (P3): E2E tests for BindingId lookup
- tests/normalized_joinir_min.rs: Added 2 new tests (lines 2182-2222)
- test_phase80_p3_bindingid_lookup_works(): Pattern3 verification
- test_phase80_p4_bindingid_lookup_works(): Pattern4 verification
- Manual fallback detection via NYASH_JOINIR_DEBUG=1

Task P4: Cleanup
- Fixed unused variable warnings (loop_var_join_id → _loop_var_join_id)
- Fixed unnecessary mut warning (cargo fix auto-applied)
- pattern2_with_break.rs: Clean up pre-existing unused warning

Result: BindingId operational across Pattern2/3/4
Tests: 970/970 PASS (baseline, E2E tests in normalized_dev feature)
Design: dev-only, dual-path maintained, zero production impact

Phase 74-80 complete: BindingId migration fully operational across all patterns

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

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

src/mir/builder/control_flow/joinir/patterns/pattern2_with_break.rs

@@ -104,7 +104,7 @@ fn prepare_pattern2_inputs(
 
     // Value space + condition env
     let mut join_value_space = JoinValueSpace::new();
-    let (mut env, mut condition_bindings, loop_var_join_id) =
+    let (mut env, mut condition_bindings, _loop_var_join_id) =
         ConditionEnvBuilder::build_for_break_condition_v2(
             condition,
             &loop_var_name,
@@ -116,13 +116,13 @@ fn prepare_pattern2_inputs(
     // Phase 79-2: Register loop variable BindingId (dev-only)
     #[cfg(feature = "normalized_dev")]
     if let Some(loop_var_bid) = builder.binding_map.get(&loop_var_name).copied() {
-        env.register_loop_var_binding(loop_var_bid, loop_var_join_id);
+        env.register_loop_var_binding(loop_var_bid, _loop_var_join_id);
         log_pattern2(
             verbose,
             "phase79",
             format!(
                 "Registered loop var BindingId: '{}' BindingId({}) → ValueId({})",
-                loop_var_name, loop_var_bid.0, loop_var_join_id.0
+                loop_var_name, loop_var_bid.0, _loop_var_join_id.0
             ),
         );
     }

src/mir/builder/control_flow/joinir/patterns/pattern3_with_if_phi.rs

@@ -128,6 +128,36 @@ impl MirBuilder {
                 &mut join_value_space,
             )?;
 
+        // Phase 80-B (P1): Register BindingIds for condition variables (dev-only)
+        #[cfg(feature = "normalized_dev")]
+        {
+            // Register loop variable BindingId
+            if let Some(bid) = self.binding_map.get(&loop_var_name) {
+                cond_env.register_loop_var_binding(*bid, _loop_var_join_id);
+                if debug {
+                    eprintln!(
+                        "[phase80/p3] Registered loop var '{}' BindingId({}) -> ValueId({})",
+                        loop_var_name, bid.0, _loop_var_join_id.0
+                    );
+                }
+            }
+
+            // Register condition binding BindingIds
+            // These are variables from the condition expression (e.g., "len" in "i < len")
+            // May include ConditionOnly carriers if they appear in the condition
+            for binding in &condition_bindings {
+                if let Some(bid) = self.binding_map.get(&binding.name) {
+                    cond_env.register_condition_binding(*bid, binding.join_value);
+                    if debug {
+                        eprintln!(
+                            "[phase80/p3] Registered condition binding '{}' BindingId({}) -> ValueId({})",
+                            binding.name, bid.0, binding.join_value.0
+                        );
+                    }
+                }
+            }
+        }
+
         trace::trace().debug(
             "pattern3/if-sum",
             &format!("ConditionEnv bindings = {}", condition_bindings.len()),

src/mir/builder/control_flow/joinir/patterns/pattern4_with_continue.rs

@@ -338,6 +338,9 @@ fn lower_pattern4_joinir(
 
     let mut join_value_space = JoinValueSpace::new();
 
+    #[cfg(feature = "normalized_dev")]
+    let binding_map_clone = builder.binding_map.clone();
+
     let (join_module, exit_meta) = match lower_loop_with_continue_minimal(
         prepared.loop_scope.clone(),
         condition,
@@ -345,6 +348,8 @@ fn lower_pattern4_joinir(
         &prepared.carrier_info,
         &prepared.carrier_updates,
         &mut join_value_space,
+        #[cfg(feature = "normalized_dev")]
+        Some(&binding_map_clone),
     ) {
         Ok(result) => result,
         Err(e) => {