perf(images): coalesce duplicate in-flight Coil network requests

Switch the three image NetworkFetcher sites from
ConcurrentRequestStrategy.UNCOORDINATED to DeDupeConcurrentRequestStrategy,
Coil's coordinated default. UNCOORDINATED let every request hit the
network independently, so the same avatar across many visible feed
notes became N parallel downloads competing for the per-host
dispatcher slots and queueing the genuinely distinct images behind
them. The de-duping strategy lets concurrent requests for a URL share
the first download and then read from disk.

https://claude.ai/code/session_01BeWZGTz48kzURQLTYyN5x9

amethyst/src/main/java/com/vitorpamplona/amethyst/service/images/BlossomFetcher.kt

@@ -27,8 +27,8 @@ import coil3.annotation.ExperimentalCoilApi
 import coil3.fetch.FetchResult
 import coil3.fetch.Fetcher
 import coil3.network.CacheStrategy
-import coil3.network.ConcurrentRequestStrategy
 import coil3.network.ConnectivityChecker
+import coil3.network.DeDupeConcurrentRequestStrategy
 import coil3.network.NetworkFetcher
 import coil3.network.okhttp.asNetworkClient
 import coil3.request.Options
@@ -74,7 +74,7 @@ class BlossomFetcher(
                     diskCache = lazy { imageLoader.diskCache },
                     cacheStrategy = lazy { CacheStrategy.DEFAULT },
                     connectivityChecker = lazy { connectivityCheckerLazy.get(options.context) },
-                    concurrentRequestStrategy = lazy { ConcurrentRequestStrategy.UNCOORDINATED },
+                    concurrentRequestStrategy = lazy { DeDupeConcurrentRequestStrategy() },
                 )
             }
         }

amethyst/src/main/java/com/vitorpamplona/amethyst/service/images/ImageLoaderSetup.kt

@@ -33,8 +33,8 @@ import coil3.gif.AnimatedImageDecoder
 import coil3.gif.GifDecoder
 import coil3.memory.MemoryCache
 import coil3.network.CacheStrategy
-import coil3.network.ConcurrentRequestStrategy
 import coil3.network.ConnectivityChecker
+import coil3.network.DeDupeConcurrentRequestStrategy
 import coil3.network.NetworkFetcher
 import coil3.network.okhttp.asNetworkClient
 import coil3.request.Options
@@ -149,7 +149,7 @@ class OkHttpFactory(
             diskCache = lazy { imageLoader.diskCache },
             cacheStrategy = cacheStrategyLazy,
             connectivityChecker = lazy { connectivityCheckerLazy.get(options.context) },
-            concurrentRequestStrategy = lazy { ConcurrentRequestStrategy.UNCOORDINATED },
+            concurrentRequestStrategy = lazy { DeDupeConcurrentRequestStrategy() },
         )
     }
 

amethyst/src/main/java/com/vitorpamplona/amethyst/service/images/ProfilePictureFetcher.kt

@@ -30,8 +30,8 @@ import coil3.fetch.Fetcher
 import coil3.fetch.ImageFetchResult
 import coil3.key.Keyer
 import coil3.network.CacheStrategy
-import coil3.network.ConcurrentRequestStrategy
 import coil3.network.ConnectivityChecker
+import coil3.network.DeDupeConcurrentRequestStrategy
 import coil3.network.NetworkFetcher
 import coil3.network.okhttp.asNetworkClient
 import coil3.request.Options
@@ -113,7 +113,7 @@ class ProfilePictureFetcher(
                     diskCache = diskCacheLazy,
                     cacheStrategy = lazy { CacheStrategy.DEFAULT },
                     connectivityChecker = lazy { connectivityCheckerLazy.get(options.context) },
-                    concurrentRequestStrategy = lazy { ConcurrentRequestStrategy.UNCOORDINATED },
+                    concurrentRequestStrategy = lazy { DeDupeConcurrentRequestStrategy() },
                 )
 
             return ProfilePictureFetcher(