fix: Remove AssetsLibrary usage for iOS 26 compatibility (#366)

## Summary
- Remove the AssetsLibrary framework import and the three ALAsset-based
methods on `SYMetadata` (`metadataWithAsset:`, `metadataWithAssetURL:`,
`dictionaryWithAssetURL:`) — AssetsLibrary is removed from the iOS 26
SDK.
- These methods have zero callers in this repository (verified via
full-tree grep). The plugin's own metadata flow uses only
`metadataWithFileURL:` / `metadataWithImageData:` /
`dataWithImageData:andMetadata:`, all backed by `CGImageSource` and
unaffected.

## Relationship to #343
#343 also targets iOS 26 but migrates the ALAsset methods to PHAsset,
adding threading/iCloud/availability infrastructure for API that is not
reachable from the plugin. This PR takes the minimal path — delete the
dead code — since restoring PHAsset-equivalent functionality can happen
in a follow-up if any external consumer ever needs it.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: AlexV525

packages/flutter_image_compress_common/ios/Classes/SYPictureMetadata/SYMetadata.h

@@ -29,8 +29,6 @@
 // http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/index.html
 // http://www.exiv2.org/tags.html
 
-@class ALAsset;
-
 @interface SYMetadata : SYMetadataBase
 
 @property SYMETADATA_PROPERTY_COPY NSDictionary *originalDictionary;
@@ -72,13 +70,9 @@
 @property (nonatomic, copy, readonly)   NSString  *profileName;
 
 + (instancetype)metadataWithDictionary:(NSDictionary *)dictionary;
-+ (instancetype)metadataWithAsset:(ALAsset *)asset __TVOS_PROHIBITED;
-+ (instancetype)metadataWithAssetURL:(NSURL *)assetURL __TVOS_PROHIBITED;
 + (instancetype)metadataWithFileURL:(NSURL *)fileURL;
 + (instancetype)metadataWithImageData:(NSData *)imageData;
 
-+ (NSDictionary *)dictionaryWithAssetURL:(NSURL *)assetURL __TVOS_PROHIBITED;
-
 + (NSData *)dataWithImageData:(NSData *)imageData andMetadata:(SYMetadata *)metadata;
 
 - (NSDictionary *)differencesFromOriginalMetadataToModel;

packages/flutter_image_compress_common/ios/Classes/SYPictureMetadata/SYMetadata.m

@@ -10,10 +10,6 @@
 #import "SYMetadata.h"
 #import "NSDictionary+SY.h"
 
-#if !TARGET_OS_TV
-#import <AssetsLibrary/AssetsLibrary.h>
-#endif
-
 #define SYKeyForMetadata(name)          NSStringFromSelector(@selector(metadata##name))
 #define SYDictionaryForMetadata(name)   SYPaste(SYPaste(kCGImageProperty,name),Dictionary)
 #define SYClassForMetadata(name)        SYPaste(SYMetadata,name)
@@ -46,22 +42,6 @@ + (instancetype)metadataWithDictionary:(NSDictionary *)dictionary
     return instance;
 }
 
-+ (instancetype)metadataWithAsset:(ALAsset *)asset
-{
-#if !TARGET_OS_TV
-    ALAssetRepresentation *representation = [asset defaultRepresentation];
-    return [self metadataWithDictionary:[representation metadata]];
-#else
-    return nil;
-#endif
-}
-
-+ (instancetype)metadataWithAssetURL:(NSURL *)assetURL
-{
-    NSDictionary *dictionary = [self dictionaryWithAssetURL:assetURL];
-    return [self metadataWithDictionary:dictionary];
-}
-
 + (instancetype)metadataWithFileURL:(NSURL *)fileURL
 {
     if (!fileURL)
@@ -144,33 +124,6 @@ + (NSData *)dataWithImageData:(NSData *)imageData andMetadata:(SYMetadata *)meta
     return (success ? data : nil);
 }
 
-#pragma mark - Getting metadata
-
-+ (NSDictionary *)dictionaryWithAssetURL:(NSURL *)assetURL
-{
-#if !TARGET_OS_TV
-    __block ALAsset *assetAtUrl = nil;
-    ALAssetsLibrary* library = [[ALAssetsLibrary alloc] init];
-    
-    dispatch_semaphore_t sema = dispatch_semaphore_create(0);
-    [library assetForURL:assetURL resultBlock:^(ALAsset *asset) {
-        assetAtUrl = asset;
-        dispatch_semaphore_signal(sema);
-    } failureBlock:^(NSError *error) {
-        dispatch_semaphore_signal(sema);
-    }];
-    dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
-    
-    if (!assetAtUrl)
-        return nil;
-    
-    ALAssetRepresentation *representation = [assetAtUrl defaultRepresentation];
-    return [representation metadata];
-#else
-    return nil;
-#endif
-}
-
 #pragma mark - Mapping
 
 + (NSDictionary *)JSONKeyPathsByPropertyKey