Uploads carry the name the file came with (#83)

An upload sends its file name next to the raw bytes, and the server keeps
it in a sidecar next to the content-addressed file. Both pickers caption
every tile and row with it, and an asset made there is named after the
file instead of "Texture" / "Font". Last upload of the same content wins.

The API's own set_error_handler ignores error_reporting(), so @-silenced
warnings still throw: a missing sidecar took the whole listing down with a
500. Existence is checked instead of suppressed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

api/lib/TextureStore.php

@@ -57,10 +57,14 @@ final class TextureStore
      * The extension is derived from the sniffed content, never from anything the client
      * says, so no request can choose the name or the type of the file it creates.
      *
-     * @return array{file:string,width:int,height:int,bytes:int}
+     * `$originalName` is kept beside the file as a caption (see OriginalName) – the picture may be
+     * re-encoded on the way, so it can name a `.png` that is stored as `.webp`. That is the point:
+     * it records where the file came from, not what it now is.
+     *
+     * @return array{file:string,name:string,width:int,height:int,bytes:int}
      * @throws InvalidImageException when the bytes are not a supported image
      */
-    public function store(string $bytes): array
+    public function store(string $bytes, string $originalName = ''): array
     {
         $size = @getimagesizefromstring($bytes);
         if ($size === false) {
@@ -88,8 +92,15 @@ final class TextureStore
         if (!is_file($path)) {
             $this->writeFile($path, $bytes);
         }
+        OriginalName::write($this->dir, $file, $originalName);
 
-        return ['file' => $file, 'width' => $width, 'height' => $height, 'bytes' => strlen($bytes)];
+        return [
+            'file' => $file,
+            'name' => OriginalName::read($this->dir, $file),
+            'width' => $width,
+            'height' => $height,
+            'bytes' => strlen($bytes),
+        ];
     }
 
     /**
@@ -99,19 +110,22 @@ final class TextureStore
      * records the size, so a picker that only knew the file name could not create one without
      * decoding the picture first. An unreadable file reports 0 × 0 and the picker skips it.
      *
-     * @return list<array{file:string,width:int,height:int,bytes:int,updatedAt:string}>
+     * @return list<array{file:string,name:string,width:int,height:int,bytes:int,updatedAt:string}>
      */
     public function list(): array
     {
         $items = [];
         foreach (glob($this->dir . '/*.*') ?: [] as $path) {
             $file = basename($path);
+            // Sidecars live in the same directory and are skipped here: `{hash}.png.json` is not
+            // a valid stored name.
             if (!self::isValidName($file)) {
                 continue;
             }
             $size = @getimagesize($path);
             $items[] = [
                 'file' => $file,
+                'name' => OriginalName::read($this->dir, $file),
                 'width' => (int) ($size[0] ?? 0),
                 'height' => (int) ($size[1] ?? 0),
                 'bytes' => (int) filesize($path),
@@ -128,7 +142,11 @@ final class TextureStore
             return false;
         }
         $path = $this->dir . '/' . $file;
-        return is_file($path) && unlink($path);
+        if (!is_file($path) || !unlink($path)) {
+            return false;
+        }
+        OriginalName::delete($this->dir, $file);
+        return true;
     }
 
     /**