NPE on invalid code

Repro
```pkl
import "pkl:reflect"

class A {
a: Int
b: String
}

val = reflect.Class(A).properties.containsKey(this)
```

Output
```
An unexpected error has occurred. Would you mind filing a bug report?
Cmd+Double-click the link below to open an issue.
Please copy and paste the entire error output into the issue's description.

https://github.com/apple/pkl/issues/new

java.lang.NullPointerException

–– Pkl Error ––
None (cause has no message)

3308 | external function containsKey(key: Any): Boolean
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
at pkl.base#Map.containsKey (https://github.com/apple/pkl/blob/0.29.0/stdlib/base.pkl#L3308)

┌─ 2 repetitions of:
│
│ 8 | val = reflect.Class(A).properties.containsKey(this)
│ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
│ at test#val (file:///test.pkl, line 8)
└─

106 | text = renderer.renderDocument(value)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
at pkl.base#Module.output.text (https://github.com/apple/pkl/blob/0.29.0/stdlib/base.pkl#L106)

107 | bytes = text.encodeToBytes("UTF-8")
^^^^
at pkl.base#Module.output.bytes (https://github.com/apple/pkl/blob/0.29.0/stdlib/base.pkl#L107)

Pkl 0.29.0 (macOS 15.4.1, native)

java.lang.NullPointerException
at org.pkl.core.runtime.VmTyped.hashCode(VmTyped.java:208)
at org.organicdesign.fp.collections.Equator$Equat$1.hash(Equator.java:54)
at org.organicdesign.fp.collections.PersistentHashMap.entry(PersistentHashMap.java:306)
at org.organicdesign.fp.collections.BaseMap.containsKey(BaseMap.java:56)
at org.pkl.core.runtime.VmMap.containsKey(VmMap.java:162)
at org.pkl.core.stdlib.base.MapNodes$containsKey.eval(MapNodes.java:79)
at org.pkl.core.stdlib.base.MapNodesFactory$containsKeyNodeGen.executeGeneric(MapNodesFactory.java:504)
at org.pkl.core.ast.member.FunctionNode.executeImpl(FunctionNode.java:116)
at org.pkl.core.ast.PklRootNode.execute(PklRootNode.java:46)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.executeRootNode(OptimizedCallTarget.java:776)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.profiledPERoot(OptimizedCallTarget.java:700)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.callBoundary(OptimizedCallTarget.java:624)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTarget.invokeCallBoundary(SubstrateOptimizedCallTarget.java:124)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTargetInstalledCode.doInvoke(SubstrateOptimizedCallTargetInstalledCode.java:232)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTarget.doInvoke(SubstrateOptimizedCallTarget.java:106)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.callDirect(OptimizedCallTarget.java:556)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedDirectCallNode.call(OptimizedDirectCallNode.java:94)
at org.pkl.core.ast.expression.member.InvokeMethodVirtualNode.evalCached(InvokeMethodVirtualNode.java:134)
at org.pkl.core.ast.expression.member.InvokeMethodVirtualNodeGen.executeGeneric(InvokeMethodVirtualNodeGen.java:177)
at org.pkl.core.ast.member.TypeCheckedPropertyNode.evalTypedObjectCached(TypeCheckedPropertyNode.java:54)
at org.pkl.core.ast.member.TypeCheckedPropertyNodeGen.executeImpl(TypeCheckedPropertyNodeGen.java:79)
at org.pkl.core.ast.PklRootNode.execute(PklRootNode.java:46)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.executeRootNode(OptimizedCallTarget.java:776)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.profiledPERoot(OptimizedCallTarget.java:700)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.callBoundary(OptimizedCallTarget.java:624)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTarget.invokeCallBoundary(SubstrateOptimizedCallTarget.java:124)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTargetInstalledCode.doInvoke(SubstrateOptimizedCallTargetInstalledCode.java:232)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTarget.doInvoke(SubstrateOptimizedCallTarget.java:106)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.callDirect(OptimizedCallTarget.java:556)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.call(OptimizedCallTarget.java:502)
at org.graalvm.truffle/com.oracle.truffle.api.nodes.IndirectCallNode$1.call(IndirectCallNode.java:96)
at org.pkl.core.runtime.VmUtils.doReadMember(VmUtils.java:312)
at org.pkl.core.runtime.VmUtils.doReadMember(VmUtils.java:214)
at org.pkl.core.runtime.VmObject.force(VmObject.java:177)
at org.pkl.core.runtime.VmObject.force(VmObject.java:197)
at org.pkl.core.runtime.VmTyped.hashCode(VmTyped.java:202)
at org.organicdesign.fp.collections.Equator$Equat$1.hash(Equator.java:54)
at org.organicdesign.fp.collections.PersistentHashMap.entry(PersistentHashMap.java:306)
at org.organicdesign.fp.collections.BaseMap.containsKey(BaseMap.java:56)
at org.pkl.core.runtime.VmMap.containsKey(VmMap.java:162)
at org.pkl.core.stdlib.base.MapNodes$containsKey.eval(MapNodes.java:79)
at org.pkl.core.stdlib.base.MapNodesFactory$containsKeyNodeGen.executeAndSpecialize(MapNodesFactory.java:538)
at org.pkl.core.stdlib.base.MapNodesFactory$containsKeyNodeGen.executeGeneric(MapNodesFactory.java:513)
at org.pkl.core.ast.member.FunctionNode.executeImpl(FunctionNode.java:116)
at org.pkl.core.ast.PklRootNode.execute(PklRootNode.java:46)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.executeRootNode(OptimizedCallTarget.java:776)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.profiledPERoot(OptimizedCallTarget.java:700)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.callBoundary(OptimizedCallTarget.java:624)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTarget.invokeCallBoundary(SubstrateOptimizedCallTarget.java:124)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTargetInstalledCode.doInvoke(SubstrateOptimizedCallTargetInstalledCode.java:232)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTarget.doInvoke(SubstrateOptimizedCallTarget.java:106)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.callDirect(OptimizedCallTarget.java:556)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedDirectCallNode.call(OptimizedDirectCallNode.java:94)
at org.pkl.core.ast.expression.member.InvokeMethodVirtualNode.evalCached(InvokeMethodVirtualNode.java:134)
at org.pkl.core.ast.expression.member.InvokeMethodVirtualNodeGen.executeAndSpecialize(InvokeMethodVirtualNodeGen.java:272)
at org.pkl.core.ast.expression.member.InvokeMethodVirtualNodeGen.executeGeneric(InvokeMethodVirtualNodeGen.java:193)
at org.pkl.core.ast.member.TypeCheckedPropertyNode.evalTypedObjectCached(TypeCheckedPropertyNode.java:54)
at org.pkl.core.ast.member.TypeCheckedPropertyNodeGen.executeAndSpecialize(TypeCheckedPropertyNodeGen.java:136)
at org.pkl.core.ast.member.TypeCheckedPropertyNodeGen.executeImpl(TypeCheckedPropertyNodeGen.java:101)
at org.pkl.core.ast.PklRootNode.execute(PklRootNode.java:46)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.executeRootNode(OptimizedCallTarget.java:776)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.profiledPERoot(OptimizedCallTarget.java:700)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.callBoundary(OptimizedCallTarget.java:624)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTarget.invokeCallBoundary(SubstrateOptimizedCallTarget.java:124)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTargetInstalledCode.doInvoke(SubstrateOptimizedCallTargetInstalledCode.java:232)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTarget.doInvoke(SubstrateOptimizedCallTarget.java:106)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.callDirect(OptimizedCallTarget.java:556)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.call(OptimizedCallTarget.java:502)
at org.graalvm.truffle/com.oracle.truffle.api.nodes.IndirectCallNode$1.call(IndirectCallNode.java:96)
at org.pkl.core.runtime.VmUtils.doReadMember(VmUtils.java:312)
at org.pkl.core.runtime.VmUtils.doReadMember(VmUtils.java:214)
at org.pkl.core.runtime.VmObject.force(VmObject.java:177)
at org.pkl.core.runtime.VmObject.forceAndIterateMemberValues(VmObject.java:116)
at org.pkl.core.stdlib.AbstractRenderer.visitTyped(AbstractRenderer.java:252)
at org.pkl.core.stdlib.base.PcfRenderer.visitTyped(PcfRenderer.java:74)
at org.pkl.core.runtime.VmTyped.accept(VmTyped.java:168)
at org.pkl.core.runtime.VmValueVisitor.visit(VmValueVisitor.java:67)
at org.pkl.core.stdlib.AbstractRenderer.visit(AbstractRenderer.java:126)
at org.pkl.core.stdlib.base.PcfRenderer.visitDocument(PcfRenderer.java:159)
at org.pkl.core.stdlib.AbstractRenderer.renderDocument(AbstractRenderer.java:101)
at org.pkl.core.stdlib.base.PcfRendererNodes$renderDocument.eval(PcfRendererNodes.java:32)
at org.pkl.core.stdlib.base.PcfRendererNodesFactory$renderDocumentNodeGen.executeAndSpecialize(PcfRendererNodesFactory.java:92)
at org.pkl.core.stdlib.base.PcfRendererNodesFactory$renderDocumentNodeGen.executeGeneric(PcfRendererNodesFactory.java:83)
at org.pkl.core.ast.member.FunctionNode.executeImpl(FunctionNode.java:116)
at org.pkl.core.ast.PklRootNode.execute(PklRootNode.java:46)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.executeRootNode(OptimizedCallTarget.java:776)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.profiledPERoot(OptimizedCallTarget.java:700)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.callBoundary(OptimizedCallTarget.java:624)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTarget.invokeCallBoundary(SubstrateOptimizedCallTarget.java:124)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTargetInstalledCode.doInvoke(SubstrateOptimizedCallTargetInstalledCode.java:232)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTarget.doInvoke(SubstrateOptimizedCallTarget.java:106)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.callDirect(OptimizedCallTarget.java:556)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedDirectCallNode.call(OptimizedDirectCallNode.java:94)
at org.pkl.core.ast.expression.member.InvokeMethodVirtualNode.evalCached(InvokeMethodVirtualNode.java:134)
at org.pkl.core.ast.expression.member.InvokeMethodVirtualNodeGen.executeAndSpecialize(InvokeMethodVirtualNodeGen.java:272)
at org.pkl.core.ast.expression.member.InvokeMethodVirtualNodeGen.executeGeneric(InvokeMethodVirtualNodeGen.java:193)
at org.pkl.core.ast.member.TypeCheckedPropertyNode.evalTypedObjectCached(TypeCheckedPropertyNode.java:54)
at org.pkl.core.ast.member.TypeCheckedPropertyNodeGen.executeAndSpecialize(TypeCheckedPropertyNodeGen.java:136)
at org.pkl.core.ast.member.TypeCheckedPropertyNodeGen.executeImpl(TypeCheckedPropertyNodeGen.java:101)
at org.pkl.core.ast.PklRootNode.execute(PklRootNode.java:46)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.executeRootNode(OptimizedCallTarget.java:776)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.profiledPERoot(OptimizedCallTarget.java:700)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.callBoundary(OptimizedCallTarget.java:624)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTarget.invokeCallBoundary(SubstrateOptimizedCallTarget.java:124)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTargetInstalledCode.doInvoke(SubstrateOptimizedCallTargetInstalledCode.java:232)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTarget.doInvoke(SubstrateOptimizedCallTarget.java:106)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.callDirect(OptimizedCallTarget.java:556)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedIndirectCallNode.call(OptimizedIndirectCallNode.java:68)
at org.pkl.core.runtime.VmUtils.doReadMember(VmUtils.java:312)
at org.pkl.core.runtime.VmUtils.readMemberOrNull(VmUtils.java:241)
at org.pkl.core.ast.expression.member.ReadPropertyNode.evalObject(ReadPropertyNode.java:75)
at org.pkl.core.ast.expression.member.ReadPropertyNodeGen.executeAndSpecialize(ReadPropertyNodeGen.java:127)
at org.pkl.core.ast.expression.member.ReadPropertyNodeGen.executeGeneric(ReadPropertyNodeGen.java:95)
at org.pkl.core.ast.expression.primary.ResolveVariableNode.executeGeneric(ResolveVariableNode.java:83)
at org.pkl.core.ast.expression.member.InvokeMethodVirtualNodeGen.executeGeneric(InvokeMethodVirtualNodeGen.java:147)
at org.pkl.core.ast.member.TypeCheckedPropertyNode.evalTypedObjectCached(TypeCheckedPropertyNode.java:54)
at org.pkl.core.ast.member.TypeCheckedPropertyNodeGen.executeAndSpecialize(TypeCheckedPropertyNodeGen.java:136)
at org.pkl.core.ast.member.TypeCheckedPropertyNodeGen.executeImpl(TypeCheckedPropertyNodeGen.java:101)
at org.pkl.core.ast.PklRootNode.execute(PklRootNode.java:46)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.executeRootNode(OptimizedCallTarget.java:776)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.profiledPERoot(OptimizedCallTarget.java:700)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.callBoundary(OptimizedCallTarget.java:624)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTarget.invokeCallBoundary(SubstrateOptimizedCallTarget.java:124)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTargetInstalledCode.doInvoke(SubstrateOptimizedCallTargetInstalledCode.java:232)
at org.graalvm.truffle.runtime.svm/com.oracle.svm.truffle.api.SubstrateOptimizedCallTarget.doInvoke(SubstrateOptimizedCallTarget.java:106)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.callDirect(OptimizedCallTarget.java:556)
at org.graalvm.truffle.runtime/com.oracle.truffle.runtime.OptimizedCallTarget.call(OptimizedCallTarget.java:502)
at org.graalvm.truffle/com.oracle.truffle.api.nodes.IndirectCallNode$1.call(IndirectCallNode.java:96)
at org.pkl.core.runtime.VmUtils.doReadMember(VmUtils.java:312)
at org.pkl.core.runtime.VmUtils.readMemberOrNull(VmUtils.java:241)
at org.pkl.core.runtime.VmUtils.readMemberOrNull(VmUtils.java:204)
at org.pkl.core.runtime.VmUtils.readMember(VmUtils.java:184)
at org.pkl.core.runtime.VmUtils.readBytesProperty(VmUtils.java:179)
at org.pkl.core.EvaluatorImpl.lambda$evaluateOutputBytes$4(EvaluatorImpl.java:152)
at org.pkl.core.EvaluatorImpl.lambda$doEvaluate$15(EvaluatorImpl.java:368)
at org.pkl.core.EvaluatorImpl.doEvaluate(EvaluatorImpl.java:316)
at org.pkl.core.EvaluatorImpl.doEvaluate(EvaluatorImpl.java:364)
at org.pkl.core.EvaluatorImpl.evaluateOutputBytes(EvaluatorImpl.java:148)
at org.pkl.cli.CliEvaluator.writeOutput(CliEvaluator.kt:217)
at org.pkl.cli.CliEvaluator.doRun(CliEvaluator.kt:105)
at org.pkl.commons.cli.CliCommand.run(CliCommand.kt:46)
at org.pkl.cli.commands.EvalCommand.run(EvalCommand.kt:84)
at com.github.ajalt.clikt.core.CoreCliktCommandKt.parse(CoreCliktCommand.kt:107)
at com.github.ajalt.clikt.core.CoreCliktCommandKt.main(CoreCliktCommand.kt:78)
at com.github.ajalt.clikt.core.CoreCliktCommandKt.main(CoreCliktCommand.kt:90)
at org.pkl.cli.Main.main$lambda$0(Main.kt:26)
at org.pkl.commons.cli.CliMainKt.cliMain(CliMain.kt:33)
at org.pkl.cli.Main.main(Main.kt:26)

```

Start by reproducing the Pkl snippet and trace the failure through VmTyped.hashCode.java, VmMap.java, and MapNodes.java, as identified in the stack trace. Add a regression test for reflect.Class(A).properties.containsKey(this) and verify it no longer exposes a raw NullPointerException.

Written by the indexing model from the issue text.