refactor(core): make Array sealed now that JPMS module is declared

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

Author: dfa1

TODO.md

@@ -53,10 +53,3 @@
 ## Encodings
 
 - [ ] the classes are very long of complex, most likely we should group the impl detail in private static inner classes Encoder/Decoder
-
-- [ ] fix this comment in Array
-     /// Not declared `sealed` because the project does not declare a JPMS module —
-     /// JLS only allows cross-package `permits` inside the same named module. The
-     /// effective hierarchy is still closed: only types in this package should implement
-     /// this interface.
-     public interface Array {

core/src/main/java/io/github/dfa1/vortex/core/array/Array.java

@@ -14,12 +14,10 @@
 ///
 /// Buffers are `MemorySegment` slices backed by the memory-mapped file; lifetime
 /// is tied to the `VortexFile`'s Arena.
-///
-/// Not declared `sealed` because the project does not declare a JPMS module —
-/// JLS only allows cross-package `permits` inside the same named module. The
-/// effective hierarchy is still closed: only types in this package should implement
-/// this interface.
-public interface Array {
+public sealed interface Array
+        permits BoolArray, ByteArray, DoubleArray, EmptyArray, Float16Array, FloatArray,
+                GenericArray, IntArray, LongArray, NullArray, ShortArray, StructArray,
+                VarBinArray {
 
 	long length();