feat(joinir): Phase 79 Activation - BindingId wiring operational (dev-only)

Phase 79 の最終段階：BindingId を ExprLowerer に配線し、end-to-end で動作確認。

Key changes:
- ExprLowerer wiring:
  - scope_resolution.rs: build_condition_env_from_scope_with_binding() (BindingId-aware)
  - expr_lowerer.rs: lower_condition() uses BindingId priority lookup

- ConditionEnv extension:
  - register_loop_var_binding(): Loop var BindingId→ValueId registration
  - register_condition_binding(): Condition-only carrier BindingId→ValueId registration

- Pattern2 integration:
  - pattern2_with_break.rs: Loop var registration (Line 116-128)
  - pattern2_with_break.rs: Carrier role-based registration (Line 381-425)
  - Debug logging: [phase79] tags for registration, [binding_pilot/hit] for lookup success

- E2E tests (normalized_joinir_min.rs, debug-only):
  - test_phase79_digitpos_bindingid_lookup_works(): DigitPos pattern verification
  - test_phase79_trim_bindingid_lookup_works(): Trim pattern verification

Result: BindingId lookup actually works end-to-end
- Promoted carriers resolve via BindingId, not string hacks
- Debug: NYASH_JOINIR_DEBUG=1 shows [phase79] Registered loop var BindingId, [binding_pilot/hit] BindingId(1) -> ValueId(100)

Tests: 1025/1025 lib PASS
Design: dev-only feature-gated, dual-path maintained (BindingId priority + name fallback)

Phase 74-79 complete: BindingId migration fully operational
- Infrastructure (74-76): BindingId type, binding_map, 3-tier lookup, promoted_bindings map
- Implementation (77): DigitPos/Trim populate, legacy deprecate
- Refactoring (78-79 Refactoring): PromotedBindingRecorder, Detector/Recorder split
- Activation (80 Foundation + 79 Activation): CarrierBindingAssigner + ExprLowerer wiring

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

@@ -75,6 +75,11 @@ impl ConditionEnvBuilder {
         let loop_var_join_id = space.alloc_param();
         env.insert(loop_var_name.to_string(), loop_var_join_id);
 
+        // Phase 79-2: Register loop variable BindingId (dev-only)
+        // NOTE: We don't have access to builder.binding_map here, so this registration
+        // needs to happen at the call site (in pattern2_with_break.rs, pattern3_with_if_phi.rs, etc.)
+        // This comment serves as a reminder for future developers.
+
         // For each condition variable, allocate JoinIR-local ValueId and build binding
         for var_name in &condition_var_names {
             let host_id = variable_map.get(var_name).copied().ok_or_else(|| {

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,
@@ -113,6 +113,20 @@ fn prepare_pattern2_inputs(
             &mut join_value_space,
         )?;
 
+    // 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);
+        log_pattern2(
+            verbose,
+            "phase79",
+            format!(
+                "Registered loop var BindingId: '{}' BindingId({}) → ValueId({})",
+                loop_var_name, loop_var_bid.0, loop_var_join_id.0
+            ),
+        );
+    }
+
     log_pattern2(
         verbose,
         "phase201",
@@ -369,9 +383,36 @@ fn promote_and_prepare_carriers(
         carrier.join_id = Some(carrier_join_id);
         #[cfg(feature = "normalized_dev")]
         if let Some(binding_id) = carrier.binding_id {
-            inputs
-                .env
-                .register_carrier_binding(binding_id, carrier_join_id);
+            // Phase 79-2: Use role-specific registration method
+            use crate::mir::join_ir::lowering::carrier_info::CarrierRole;
+            match carrier.role {
+                CarrierRole::ConditionOnly => {
+                    inputs
+                        .env
+                        .register_condition_binding(binding_id, carrier_join_id);
+                    log_pattern2(
+                        verbose,
+                        "phase79",
+                        format!(
+                            "Registered condition-only carrier '{}' BindingId({}) → ValueId({})",
+                            carrier.name, binding_id.0, carrier_join_id.0
+                        ),
+                    );
+                }
+                CarrierRole::LoopState => {
+                    inputs
+                        .env
+                        .register_carrier_binding(binding_id, carrier_join_id);
+                    log_pattern2(
+                        verbose,
+                        "phase79",
+                        format!(
+                            "Registered loop-state carrier '{}' BindingId({}) → ValueId({})",
+                            carrier.name, binding_id.0, carrier_join_id.0
+                        ),
+                    );
+                }
+            }
         }
         log_pattern2(
             verbose,