perf(environment): intersect list identity candidates through a set

The list planner filtered each recording's candidate fields with a
linear includes per candidate, even on the first recording, so a
one-item list with tens of thousands of suffix-named fields cost
hundreds of millions of comparisons. The first recording's candidates
now stand as they are and later recordings intersect through a set.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/domain/analysisView/EnvironmentStateExtraction.ts

@@ -347,9 +347,13 @@ export class EnvironmentStateExtraction {
         return;
       }
       if (found === true) continue;
-      names = (names ?? found.fields).filter((name) =>
-        found.fields.includes(name),
-      );
+      // The first recording's candidates stand; later ones intersect through a set, so a wide
+      // item costs one pass per recording.
+      if (names === undefined) names = found.fields;
+      else {
+        const matching = new Set(found.fields);
+        names = names.filter((name) => matching.has(name));
+      }
       if (found.several) for (const name of found.fields) shown.add(name);
     }
     // An identity name is only inferred from items that carry it; empty lists prove none.