test: move test helpers under io.github.dfa1.vortex.core.*

DTypes, TestSegments, and ProtoRuntimeTest lived under
io.github.dfa1.vortex.encoding / io.github.dfa1.vortex.proto, outside
the documented core.* module map. Move them to
io.github.dfa1.vortex.core.testing / io.github.dfa1.vortex.core.proto
and repoint every reader/writer test's imports. Delete
EncodeTestHelper and TestRegistry, empty placeholder stubs left behind
when their real implementations moved to writer/test and reader/test.

Author: dfa1

…/dfa1/vortex/proto/ProtoRuntimeTest.java …/vortex/core/proto/ProtoRuntimeTest.javacore/src/test/java/io/github/dfa1/vortex/proto/ProtoRuntimeTest.java renamed to core/src/test/java/io/github/dfa1/vortex/core/proto/ProtoRuntimeTest.java core/src/test/java/io/github/dfa1/vortex/proto/ProtoRuntimeTest.java renamed to core/src/test/java/io/github/dfa1/vortex/core/proto/ProtoRuntimeTest.java

@@ -33,7 +33,7 @@ void roundTripsVarint64(long value) throws IOException {
         }
 
         @Test
-        void varintCanonicalEncodingOf150() throws IOException {
+        void varintCanonicalEncodingOf150() {
             // Given — proto3 spec example: 150 encodes as 0x96 0x01.
             ProtoWriter w = new ProtoWriter();
             w.writeVarint64(150L);
@@ -334,7 +334,7 @@ void recordsWithDifferentByteArraysAreNotEqual() {
     class Backpatch {
 
         @Test
-        void shortPayloadCompactsLengthVarint() throws IOException {
+        void shortPayloadCompactsLengthVarint() {
             // Given — payload of 3 bytes fits in 1-byte varint length.
             // beginLenDelim reserves 5 bytes; endLenDelim shifts the payload left by 4.
             ProtoWriter w = new ProtoWriter();
@@ -352,7 +352,7 @@ void shortPayloadCompactsLengthVarint() throws IOException {
         }
 
         @Test
-        void backpatchedMatchesLegacyEmbeddedPattern() throws IOException {
+        void backpatchedMatchesLegacyEmbeddedPattern() {
             // Given — same packed varint payload via backpatch vs. the legacy
             // "temp ProtoWriter + writeEmbedded" pattern. Output bytes must match exactly,
             // proving the backpatch refactor is wire-compatible.

…/github/dfa1/vortex/encoding/DTypes.java …hub/dfa1/vortex/core/testing/DTypes.javacore/src/test/java/io/github/dfa1/vortex/encoding/DTypes.java renamed to core/src/test/java/io/github/dfa1/vortex/core/testing/DTypes.java core/src/test/java/io/github/dfa1/vortex/encoding/DTypes.java renamed to core/src/test/java/io/github/dfa1/vortex/core/testing/DTypes.java

@@ -1,4 +1,4 @@
-package io.github.dfa1.vortex.encoding;
+package io.github.dfa1.vortex.core.testing;
 
 import io.github.dfa1.vortex.core.model.DType;
 import io.github.dfa1.vortex.core.model.PType;

…b/dfa1/vortex/encoding/TestSegments.java …a1/vortex/core/testing/TestSegments.javacore/src/test/java/io/github/dfa1/vortex/encoding/TestSegments.java renamed to core/src/test/java/io/github/dfa1/vortex/core/testing/TestSegments.java core/src/test/java/io/github/dfa1/vortex/encoding/TestSegments.java renamed to core/src/test/java/io/github/dfa1/vortex/core/testing/TestSegments.java

@@ -1,4 +1,4 @@
-package io.github.dfa1.vortex.encoding;
+package io.github.dfa1.vortex.core.testing;
 
 import io.github.dfa1.vortex.core.io.VortexFormat;
 

core/src/test/java/io/github/dfa1/vortex/encoding/EncodeTestHelper.java

@@ -3,7 +3,7 @@
 import io.github.dfa1.vortex.core.error.VortexException;
 import io.github.dfa1.vortex.reader.array.Array;
 import io.github.dfa1.vortex.reader.array.UnknownArray;
-import io.github.dfa1.vortex.encoding.DTypes;
+import io.github.dfa1.vortex.core.testing.DTypes;
 import io.github.dfa1.vortex.core.model.EncodingId;
 import io.github.dfa1.vortex.reader.decode.ArrayNode;
 import io.github.dfa1.vortex.reader.decode.DecodeContext;

core/src/test/java/io/github/dfa1/vortex/encoding/TestRegistry.java

@@ -10,13 +10,13 @@
 import java.lang.foreign.MemorySegment;
 import java.util.List;
 
-import static io.github.dfa1.vortex.encoding.DTypes.BOOL;
-import static io.github.dfa1.vortex.encoding.DTypes.F32;
-import static io.github.dfa1.vortex.encoding.DTypes.F64;
-import static io.github.dfa1.vortex.encoding.DTypes.I16;
-import static io.github.dfa1.vortex.encoding.DTypes.I32;
-import static io.github.dfa1.vortex.encoding.DTypes.I64;
-import static io.github.dfa1.vortex.encoding.DTypes.I8;
+import static io.github.dfa1.vortex.core.testing.DTypes.BOOL;
+import static io.github.dfa1.vortex.core.testing.DTypes.F32;
+import static io.github.dfa1.vortex.core.testing.DTypes.F64;
+import static io.github.dfa1.vortex.core.testing.DTypes.I16;
+import static io.github.dfa1.vortex.core.testing.DTypes.I32;
+import static io.github.dfa1.vortex.core.testing.DTypes.I64;
+import static io.github.dfa1.vortex.core.testing.DTypes.I8;
 import static io.github.dfa1.vortex.reader.array.TestArrays.bools;
 import static io.github.dfa1.vortex.reader.array.TestArrays.bytes;
 import static io.github.dfa1.vortex.reader.array.TestArrays.doubles;

reader/src/test/java/io/github/dfa1/vortex/reader/ReadRegistryTest.java

@@ -14,8 +14,8 @@
 import java.math.BigDecimal;
 import java.util.List;
 
-import static io.github.dfa1.vortex.encoding.DTypes.F64;
-import static io.github.dfa1.vortex.encoding.DTypes.I64;
+import static io.github.dfa1.vortex.core.testing.DTypes.F64;
+import static io.github.dfa1.vortex.core.testing.DTypes.I64;
 import static io.github.dfa1.vortex.reader.array.TestArrays.bools;
 import static io.github.dfa1.vortex.reader.array.TestArrays.bytes;
 import static io.github.dfa1.vortex.reader.array.TestArrays.doubles;

reader/src/test/java/io/github/dfa1/vortex/reader/array/ArrayLimitedTest.java

@@ -10,13 +10,13 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import static io.github.dfa1.vortex.encoding.DTypes.BOOL;
-import static io.github.dfa1.vortex.encoding.DTypes.F32;
-import static io.github.dfa1.vortex.encoding.DTypes.F64;
-import static io.github.dfa1.vortex.encoding.DTypes.I16;
-import static io.github.dfa1.vortex.encoding.DTypes.I32;
-import static io.github.dfa1.vortex.encoding.DTypes.I64;
-import static io.github.dfa1.vortex.encoding.DTypes.I8;
+import static io.github.dfa1.vortex.core.testing.DTypes.BOOL;
+import static io.github.dfa1.vortex.core.testing.DTypes.F32;
+import static io.github.dfa1.vortex.core.testing.DTypes.F64;
+import static io.github.dfa1.vortex.core.testing.DTypes.I16;
+import static io.github.dfa1.vortex.core.testing.DTypes.I32;
+import static io.github.dfa1.vortex.core.testing.DTypes.I64;
+import static io.github.dfa1.vortex.core.testing.DTypes.I8;
 import static io.github.dfa1.vortex.reader.array.TestArrays.bools;
 import static io.github.dfa1.vortex.reader.array.TestArrays.bytes;
 import static io.github.dfa1.vortex.reader.array.TestArrays.doubles;

reader/src/test/java/io/github/dfa1/vortex/reader/array/ArrayMaterializeTest.java

@@ -1,7 +1,7 @@
 package io.github.dfa1.vortex.reader.array;
 
 import io.github.dfa1.vortex.core.error.VortexException;
-import io.github.dfa1.vortex.encoding.DTypes;
+import io.github.dfa1.vortex.core.testing.DTypes;
 import org.junit.jupiter.api.Test;
 
 import java.lang.foreign.Arena;