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/using_prefix_strict_smoke.sh

@@ -3,7 +3,7 @@ set -euo pipefail
 [[ "${NYASH_CLI_VERBOSE:-0}" == "1" ]] && set -x
 
 ROOT_DIR=$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)
-BIN="$ROOT_DIR/target/release/nyash"
+BIN="$ROOT_DIR/target/release/hakorune"
 
 if [ ! -x "$BIN" ]; then
   cargo build --release >/dev/null