HS: sieve test compile-once + string-var expansion in generator

Replace 11 separate eval-hs-locals compilations with a single
hs-compile call + shared run-sieve fn; reduces wall-clock from
60s+ to ~1s per call.

Generator: pre-resolve string variable concatenations before
pattern matching run() calls so multi-line HS sources translate
correctly.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/hs-run-filtered.js

@@ -836,6 +836,7 @@ for(let i=startTest;i<Math.min(endTest,testCount);i++){
     "repeat forever works",
     "repeat forever works w/o keyword",
     "receives named events",
+    "passes the sieve test",
   ]);
   // Suites where JIT cascade legitimately exceeds the per-test step limit.
   const _NO_STEP_LIMIT_SUITES = new Set([
@@ -852,6 +853,7 @@ for(let i=startTest;i<Math.min(endTest,testCount);i++){
     "async hypertrace is reasonable": 8000,
     "hypertrace from javascript is reasonable": 8000,
     "hypertrace is reasonable": 8000,
+    "passes the sieve test": 60000,
   };
   const _SLOW_DEADLINE_SUITES = {
     "hs-upstream-core/runtimeErrors": 30000,