Adopt Go-style minimal interfaces for streams

Replace PSR-7 StreamInterface with a set of small, composable interfaces
(ReaderInterface, WriterInterface, SeekerInterface and their
combinations).
BinaryReader now depends only on ReaderInterface, BinaryWriter on
WriterInterface, making both easy to satisfy with any byte source or
sink.

Buffer and Resource are simplified — no capability flags, no
detach/close
lifecycle, no PSR-7 metadata methods. LimitedResource is replaced by
LimitedReader, a lightweight reader that enforces a byte count limit.
BinaryReader::read() is renamed to readExact() for clarity.

Tests updated throughout to match the new APIs.

tests/Unit/ResourceTest.php

@@ -3,66 +3,90 @@
 use Shufflingpixels\IO\Exception\IOException;
 use Shufflingpixels\IO\Resource;
 
-it('reads, writes, seeks and reports stream state', function () {
-    $handle = fopen('php://temp', 'r+');
-    fwrite($handle, 'hello');
-    rewind($handle);
+function makeResource(string $mode = 'r+', string $initial = ''): Resource
+{
+    $handle = fopen('php://temp', $mode);
+    if ($initial !== '') {
+        fwrite($handle, $initial);
+        rewind($handle);
+    }
 
-    $stream = new class($handle, true, true, true) extends Resource {
-        public function __construct($resource, bool $seekable, bool $readable, bool $writeable)
-        {
-            parent::__construct($resource, $seekable, $readable, $writeable);
-        }
+    return new class($handle) extends Resource {
+        public function __construct(mixed $resource) { parent::__construct($resource); }
     };
+}
 
-    expect($stream->getSize())->toBe(5)
+it('reads, writes, seeks and reports length', function () {
+    $stream = makeResource('r+', 'hello');
+
+    expect($stream->length())->toBe(5)
         ->and($stream->tell())->toBe(0)
-        ->and($stream->isSeekable())->toBeTrue()
-        ->and($stream->isReadable())->toBeTrue()
-        ->and($stream->isWritable())->toBeTrue()
         ->and($stream->read(2))->toBe('he');
 
     $stream->seek(0);
     expect($stream->write('H'))->toBe(1);
 
     $stream->seek(0);
-    expect($stream->read(5))->toBe('Hello')
-        ->and($stream->getSize())->toBe(5)
-        ->and($stream->eof())->toBeFalse();
+    expect($stream->read(5))->toBe('Hello');
+});
+
+it('length is recalculated after a write', function () {
+    $stream = makeResource('r+', 'abc');
+
+    expect($stream->length())->toBe(3);
+
+    $stream->seek(0, SEEK_END);
+    $stream->write('de');
+
+    expect($stream->length())->toBe(5);
+});
+
+it('eof is true only after reading past the end', function () {
+    $stream = makeResource('r+', 'ab');
+
+    expect($stream->eof())->toBeFalse();
+
+    $stream->read(3);
 
-    $stream->read(1);
     expect($stream->eof())->toBeTrue();
-
-    $stream->close();
 });
 
-it('throws when seeking or getting length on non-seekable stream', function () {
-    $handle = fopen('php://temp', 'r+');
+it('returns false when reading at end of stream', function () {
+    $stream = makeResource('r+', 'ab');
+    $stream->read(3);
 
-    $stream = new class($handle, false, true, false) extends Resource {
-        public function __construct($resource, bool $seekable, bool $readable, bool $writeable)
-        {
-            parent::__construct($resource, $seekable, $readable, $writeable);
-        }
+    expect($stream->read(1))->toBeFalse();
+});
+
+it('seek throws IOException on failure', function () {
+    $stream = makeResource('r+', 'abc');
+
+    expect(fn () => $stream->seek(-999))->toThrow(IOException::class);
+});
+
+it('write throws IOException when the underlying fwrite fails', function () {
+    $handle = fopen('php://temp', 'r');
+    $stream = new class($handle) extends Resource {
+        public function __construct(mixed $resource) { parent::__construct($resource); }
     };
 
-    expect($stream->getSize())->toBeNull()
-        ->and(fn () => $stream->seek(0))->toThrow(IOException::class);
-
-    $stream->close();
+    expect(fn () => $stream->write('x'))->toThrow(IOException::class);
 });
 
-it('throws when writing to a non-writeable stream', function () {
-    $handle = fopen('php://temp', 'r+');
+it('close releases the resource', function () {
+    $stream = makeResource('r+', 'abc');
+    $stream->close();
 
-    $stream = new class($handle, true, true, false) extends Resource {
-        public function __construct($resource, bool $seekable, bool $readable, bool $writeable)
-        {
-            parent::__construct($resource, $seekable, $readable, $writeable);
-        }
+    expect(fn () => $stream->read(1))->toThrow(\TypeError::class);
+});
+
+it('detach returns the underlying resource', function () {
+    $handle = fopen('php://temp', 'r+');
+    $stream = new class($handle) extends Resource {
+        public function __construct(mixed $resource) { parent::__construct($resource); }
     };
 
-    expect(fn () => $stream->write('x'))->toThrow(IOException::class, 'not writeable');
+    $detached = $stream->detach();
 
-    $stream->close();
+    expect($detached)->toBe($handle);
 });