fix(cache): replace custom ETag strategy with OkHttp native cache

Drop ETagCacheStrategy, ETagOfflineFallbackInterceptor, and per-request
etagRevalidation() in favor of OkHttp built-in HTTP cache. This gives
us max-age freshness, conditional If-None-Match revalidation, and offline
stale-serve out of the box. Coil disk cache is disabled so OkHttp is
the single disk layer, fixing the icons-flashing-on-launch bug caused by
Coil DefaultCacheStrategy bypassing freshness checks.

Signed-off-by: Brandon McAnsh <git@bmcreations.dev>

Author: bmc08gt

apps/flipcash/app/src/main/kotlin/com/flipcash/app/FlipcashApp.kt

@@ -7,15 +7,12 @@ import androidx.work.Configuration
 import coil3.ImageLoader
 import coil3.PlatformContext
 import coil3.SingletonImageLoader
-import coil3.annotation.ExperimentalCoilApi
-import coil3.disk.DiskCache
-import coil3.disk.directory
 import coil3.network.okhttp.OkHttpNetworkFetcherFactory
 import coil3.request.CachePolicy
 import coil3.request.crossfade
 import com.flipcash.app.auth.AuthManager
-import com.flipcash.app.core.cache.ETagCacheStrategy
-import com.flipcash.app.core.cache.ETagOfflineFallbackInterceptor
+import okhttp3.Cache
+import okhttp3.OkHttpClient
 import com.flipcash.app.currency.PreferredCurrencyController
 import com.getcode.opencode.repositories.EventRepository
 import com.getcode.utils.trace
@@ -53,23 +50,16 @@ class FlipcashApp : Application(), Configuration.Provider, SingletonImageLoader.
         trace("app onCreate end")
     }
 
-    @OptIn(ExperimentalCoilApi::class)
     override fun newImageLoader(context: PlatformContext): ImageLoader {
+        val okHttpClient = OkHttpClient.Builder()
+            .cache(Cache(context.cacheDir.resolve("http_image_cache"), 50L * 1024 * 1024))
+            .build()
         return ImageLoader.Builder(context)
             .crossfade(true)
             .memoryCachePolicy(CachePolicy.ENABLED)
-            .diskCachePolicy(CachePolicy.ENABLED)
-            .diskCache {
-                DiskCache.Builder()
-                    .directory(context.cacheDir.resolve("image_cache"))
-                    .maxSizePercent(0.2)
-                    .build()
-            }
+            .diskCachePolicy(CachePolicy.DISABLED)
             .components {
-                add(ETagOfflineFallbackInterceptor())
-                add(OkHttpNetworkFetcherFactory(
-                    cacheStrategy = { ETagCacheStrategy() },
-                ))
+                add(OkHttpNetworkFetcherFactory(callFactory = { okHttpClient }))
             }
             .build()
     }

apps/flipcash/core/src/main/kotlin/com/flipcash/app/core/cache/ETagRevalidation.kt

@@ -20,7 +20,6 @@ import coil3.compose.LocalPlatformContext
 import coil3.request.ImageRequest
 import coil3.request.crossfade
 import coil3.request.error
-import com.flipcash.app.core.cache.etagRevalidation
 import com.getcode.opencode.model.financial.Token
 import com.getcode.theme.CodeTheme
 import com.getcode.ui.components.R
@@ -108,7 +107,6 @@ fun TokenIcon(
             .data(image)
             .crossfade(false)
             .error(R.drawable.ic_placeholder_user)
-            .etagRevalidation()
             .build(),
         contentDescription = null,
         contentScale = ContentScale.Crop,