fix(nip73): honor data-saver gate and fix preview icon touch target

Review feedback from PR #3810:

- Gate both new preview call sites behind settings.showUrlPreview(), so a
  user on WIFI_ONLY over cellular or NEVER no longer triggers an outbound
  OpenGraph request and image download per external-scoped comment. Falls
  back to the plain link chip / URL header.
- Wrap the open-in-browser icon in an IconButton so it gets a real touch
  target instead of a 14dp one nested inside the card's own clickable,
  where a near-miss silently navigated instead.
- Only show that icon when onCardClick is set; without it the icon and the
  card tap did the same thing, so existing note-body link cards stay as-is.
- staticCompositionLocalOf for LocalCurrentExternalScope (constant per
  screen, avoids read tracking per feed row).
- Inset the loading/error URL header to match the card, and use the
  hoisted Size14Modifier.

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/components/UrlPreviewCard.kt

@@ -21,12 +21,11 @@
 package com.vitorpamplona.amethyst.ui.components
 
 import androidx.compose.foundation.ExperimentalFoundationApi
-import androidx.compose.foundation.clickable
 import androidx.compose.foundation.combinedClickable
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
-import androidx.compose.foundation.layout.size
+import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
@@ -40,7 +39,6 @@ import androidx.compose.ui.layout.ContentScale
 import androidx.compose.ui.platform.LocalClipboard
 import androidx.compose.ui.platform.LocalUriHandler
 import androidx.compose.ui.text.style.TextOverflow
-import androidx.compose.ui.unit.dp
 import coil3.compose.AsyncImage
 import com.vitorpamplona.amethyst.R
 import com.vitorpamplona.amethyst.commons.icons.symbols.Icon
@@ -50,6 +48,7 @@ import com.vitorpamplona.amethyst.ui.components.util.setText
 import com.vitorpamplona.amethyst.ui.stringRes
 import com.vitorpamplona.amethyst.ui.theme.DoubleVertSpacer
 import com.vitorpamplona.amethyst.ui.theme.MaxWidthWithHorzPadding
+import com.vitorpamplona.amethyst.ui.theme.Size14Modifier
 import com.vitorpamplona.amethyst.ui.theme.innerPostModifier
 import com.vitorpamplona.amethyst.ui.theme.previewCardImageModifier
 import kotlinx.coroutines.launch
@@ -134,17 +133,20 @@ fun UrlPreviewCard(
                 overflow = TextOverflow.Ellipsis,
             )
 
-            Spacer(modifier = Modifier.size(4.dp))
-
-            Icon(
-                symbol = MaterialSymbols.AutoMirrored.OpenInNew,
-                contentDescription = stringRes(R.string.url_preview_open_in_browser),
-                modifier =
-                    Modifier
-                        .size(14.dp)
-                        .clickable { runCatching { uri.openUri(url) } },
-                tint = Color.Gray,
-            )
+            // Only meaningful when the card's own tap does something else (e.g. opening the
+            // comment thread); otherwise it would duplicate the card's open-in-browser tap.
+            if (onCardClick != null) {
+                IconButton(
+                    onClick = { runCatching { uri.openUri(url) } },
+                ) {
+                    Icon(
+                        symbol = MaterialSymbols.AutoMirrored.OpenInNew,
+                        contentDescription = stringRes(R.string.url_preview_open_in_browser),
+                        modifier = Size14Modifier,
+                        tint = Color.Gray,
+                    )
+                }
+            }
         }
 
         Text(

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/nip22Comments/DisplayExternalId.kt

@@ -28,7 +28,7 @@ import androidx.compose.material3.LocalTextStyle
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.compositionLocalOf
+import androidx.compose.runtime.staticCompositionLocalOf
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.text.LinkAnnotation
@@ -62,7 +62,7 @@ import com.vitorpamplona.quartz.nip73ExternalIds.urls.UrlId
  * the URL thread screen) provides this so nested comments sharing that same scope don't
  * redundantly repeat the preview the screen itself already shows.
  */
-val LocalCurrentExternalScope = compositionLocalOf<String?> { null }
+val LocalCurrentExternalScope = staticCompositionLocalOf<String?> { null }
 
 @Composable
 fun DisplayExternalId(
@@ -96,12 +96,8 @@ fun DisplayUrlExternalId(
     nav: INav,
 ) {
     val url = externalId.url
-    when (val state = rememberUrlPreviewState(url, accountViewModel)) {
-        is UrlPreviewState.Loaded -> {
-            UrlPreviewCard(url, state.previewInfo, onCardClick = { nav.nav(Route.Url(url)) })
-        }
-
-        else -> {
+    val chip =
+        @Composable {
             DisplayExternalIdChip(
                 symbol = MaterialSymbols.Link,
                 contentDescription = stringRes(id = R.string.external_url_scope),
@@ -109,6 +105,22 @@ fun DisplayUrlExternalId(
                 linkInteractionListener = { nav.nav(Route.Url(url)) },
             )
         }
+
+    // Respect the data-saver/privacy gate: fetching the preview reaches out to the
+    // third-party page, so when previews are off this stays a plain link chip.
+    if (!accountViewModel.settings.showUrlPreview()) {
+        chip()
+        return
+    }
+
+    when (val state = rememberUrlPreviewState(url, accountViewModel)) {
+        is UrlPreviewState.Loaded -> {
+            UrlPreviewCard(url, state.previewInfo, onCardClick = { nav.nav(Route.Url(url)) })
+        }
+
+        else -> {
+            chip()
+        }
     }
 }
 

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/url/UrlScreen.kt

@@ -44,6 +44,7 @@ import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.url.dal.UrlFeedViewModel
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.url.datasource.UrlFilterAssemblerSubscription
 import com.vitorpamplona.amethyst.ui.stringRes
+import com.vitorpamplona.amethyst.ui.theme.MaxWidthWithHorzPadding
 import com.vitorpamplona.quartz.nip73ExternalIds.urls.UrlId
 
 @Composable
@@ -131,13 +132,20 @@ fun UrlScreenPreview(
     url: String,
     accountViewModel: AccountViewModel,
 ) {
+    // Respect the data-saver/privacy gate: fetching the preview reaches out to the
+    // third-party page, so when previews are off this stays the plain URL header.
+    if (!accountViewModel.settings.showUrlPreview()) {
+        DisplayUrlHeader(url, MaxWidthWithHorzPadding)
+        return
+    }
+
     when (val state = rememberUrlPreviewState(url, accountViewModel)) {
         is UrlPreviewState.Loaded -> {
             UrlPreviewCard(url, state.previewInfo)
         }
 
         else -> {
-            DisplayUrlHeader(url, Modifier)
+            DisplayUrlHeader(url, MaxWidthWithHorzPadding)
         }
     }
 }