fix(javascript): preserve loader-specific package ancestry

Require a package directory for bare ESM imports. Continue CommonJS root and subpath lookup through ancestor packages after ordinary misses, while keeping exports authority, unavailable metadata, and failed nonempty main entrypoints terminal.

Carry failed-main ownership in the internal resolution result and retain the nearest local miss after exhausting ancestors. Consolidate package selection at its owning boundary and qualify loader differences with real Node 24, CLI, and MCP regressions.

src/application/javascript/JavaScriptArtifactPathResolution.ts

@@ -100,6 +100,8 @@ type CandidateResolution =
       readonly resolvedPath: null;
       readonly status: UnresolvedArtifactPathStatus;
       readonly limitations: readonly string[];
+      /** A truthy package main failed, so Node must not try ancestor packages. */
+      readonly stopsAncestorLookup?: true;
     };
 
 /** Resolve one declaration while preserving its original input identity. */
@@ -274,23 +276,39 @@ const bareModuleCandidate = (
   }
   const source = input.files.get(input.sourcePath);
   let directory = posix.dirname(input.sourcePath);
+  let nearestNotFound: CandidateResolution | null = null;
   while (true) {
     const candidate = posix.join(directory, dependencyDirectory);
     const metadata = readPackageMetadata(input, candidate);
-    if (request.dependencyExportsEligible && metadata.kind !== "absent")
-      return resolvePackageDependency(input, candidate, request, metadata);
-    if (request.packageSubpath === ".") {
-      const direct = resolveFileCandidates(
-        input,
-        fileCandidates(candidate, input.moduleKind),
-      );
-      if (direct !== null) return direct;
+    const continueCommonJsLookup =
+      input.moduleKind === "require" &&
+      (metadata.kind === "absent" ||
+        (metadata.kind === "available" &&
+          (!request.dependencyExportsEligible ||
+            metadata.exports === undefined)));
+    const packageResolution =
+      metadata.kind !== "absent" ||
+      hasContainerDirectory(input.files, candidate, source?.container_sha256)
+        ? resolvePackageDependency(input, candidate, request, metadata)
+        : request.packageSubpath === "." && input.moduleKind !== "import"
+          ? resolveFileCandidates(
+              input,
+              fileCandidates(candidate, input.moduleKind),
+            )
+          : null;
+    if (packageResolution !== null) {
+      if (
+        continueCommonJsLookup &&
+        packageResolution.status === "not-found" &&
+        packageResolution.stopsAncestorLookup !== true
+      ) {
+        nearestNotFound ??= packageResolution;
+      } else return packageResolution;
     }
-    if (hasContainerDirectory(input.files, candidate, source?.container_sha256))
-      return resolvePackageDependency(input, candidate, request, metadata);
     if (directory === "." || directory === "") break;
     directory = posix.dirname(directory);
   }
+  if (nearestNotFound !== null) return nearestNotFound;
   return unresolvedCandidate("external", [
     "No matching bare package was inventoried in an enclosing node_modules directory.",
   ]);
@@ -425,10 +443,12 @@ const resolvePackageDependency = (
   if (rawExports === undefined) {
     if (subpath === ".")
       return (
-        resolveFileCandidates(
-          input,
-          fileCandidates(directory, input.moduleKind),
-        ) ?? resolveDirectory(input, directory, metadata, new Set())
+        (input.moduleKind === "import"
+          ? null
+          : resolveFileCandidates(
+              input,
+              fileCandidates(directory, input.moduleKind),
+            )) ?? resolveDirectory(input, directory, metadata, new Set())
       );
     // Resolve legacy ESM subpaths as URLs: suffixes identify the loaded module
     // but do not belong to its filesystem path. Keep the declared specifier on
@@ -831,6 +851,8 @@ const resolveDirectory = (
     ]) ??
     resolveFileCandidates(input, indexCandidates(directory, input.moduleKind));
   if (selected !== null) return selected;
+  if (input.moduleKind === "require")
+    return { ...notFoundCandidate(), stopsAncestorLookup: true };
   if (input.moduleKind !== undefined) return notFoundCandidate();
   return resolveCandidate(
     entryInput,
@@ -1102,7 +1124,10 @@ const packageExportConditions = (
     "default",
   ]);
 
-const notFoundCandidate = (): CandidateResolution => ({
+const notFoundCandidate = (): Extract<
+  CandidateResolution,
+  { readonly resolvedPath: null }
+> => ({
   resolvedPath: null,
   status: "not-found",
   limitations: [