feat(joinir): Phase 213-2 Step 2-2 & 2-3 Data structure extensions

Extended PatternPipelineContext and CarrierUpdateInfo for Pattern 3 AST-based generalization.

Changes:
1. PatternPipelineContext:
   - Added loop_condition: Option<ASTNode>
   - Added loop_body: Option<Vec<ASTNode>>
   - Added loop_update_summary: Option<LoopUpdateSummary>
   - Updated build_pattern_context() for Pattern 3

2. CarrierUpdateInfo:
   - Added then_expr: Option<ASTNode>
   - Added else_expr: Option<ASTNode>
   - Updated analyze_loop_updates() with None defaults

Status: Phase 213-2 Steps 2-2 & 2-3 complete
Next: Create Pattern3IfAnalyzer to extract if statement and populate update summary

tools/pyvm_vs_llvmlite.sh

@@ -27,7 +27,8 @@ set -e
 # 3) Run PyVM path (VM mode delegated to Python)
 echo "[cmp] running PyVM ..." >&2
 set +e
-OUT_PY=$(NYASH_VM_USE_PY=1 ./target/release/nyash --backend vm "$APP" 2>&1)
+BIN=${NYASH_BIN:-./target/release/hakorune}
+OUT_PY=$(NYASH_VM_USE_PY=1 "$BIN" --backend vm "$APP" 2>&1)
 CODE_PY=$?
 set -e