feat: render nowhere links inline as branded cards

Nowhere (https://github.com/5t34k/nowhere) encodes whole mini-sites in
a URL fragment, so the OpenGraph preview path returns nothing useful and
hostednowhere.com 403s scrapers. Detect URLs on hostednowhere.com and
nowhr.xyz that carry a fragment as a NowhereLinkSegment and render them
through a NowhereLinkCard that labels the tool type (Event, Store,
Message, ...) and opens the URL in the browser on click.

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/richtext/RichTextParser.kt

@@ -332,6 +332,10 @@ class RichTextParser {
             }
         }
 
+        if (urls.withoutScheme.contains(word) || urls.withScheme.contains(word)) {
+            parseNowhereLink(word)?.let { return it }
+        }
+
         if (urls.withoutScheme.contains(word)) return SchemelessUrlSegment(word)
 
         if (urls.withScheme.contains(word)) return LinkSegment(word)
@@ -529,6 +533,29 @@ class RichTextParser {
         }
 
         fun isUrlWithoutScheme(url: String) = noProtocolUrlValidator.matches(url)
+
+        // Nowhere links (https://github.com/5t34k/nowhere) encode an entire mini-site in the URL
+        // fragment. Servers never see the fragment, so OpenGraph previews return nothing useful
+        // (and hostednowhere.com 403s scrapers). Detect them by host + presence of a fragment
+        // so the renderer can show a branded card instead of falling through to LoadUrlPreview.
+        private val nowhereHosts = listOf("nowhr.xyz", "hostednowhere.com")
+
+        fun parseNowhereLink(word: String): NowhereLinkSegment? {
+            val afterScheme =
+                when {
+                    word.startsWith("https://", ignoreCase = true) -> word.substring(8)
+                    word.startsWith("http://", ignoreCase = true) -> word.substring(7)
+                    else -> word
+                }
+            val slash = afterScheme.indexOf('/')
+            if (slash < 0) return null
+            val host = afterScheme.substring(0, slash).lowercase()
+            if (host !in nowhereHosts) return null
+            val hash = afterScheme.indexOf('#', slash)
+            if (hash < 0) return null
+            val pathSegment = afterScheme.substring(slash + 1, hash).substringBefore('/').takeIf { it.isNotEmpty() }
+            return NowhereLinkSegment(word, host, pathSegment)
+        }
     }
 }
 

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/richtext/RichTextParserSegments.kt

@@ -158,6 +158,13 @@ class SchemelessUrlSegment(
     segment: String,
 ) : Segment(segment)
 
+@Immutable
+class NowhereLinkSegment(
+    segment: String,
+    val host: String,
+    val tool: String?,
+) : Segment(segment)
+
 @Immutable
 class RegularTextSegment(
     segment: String,

commons/src/commonTest/kotlin/com/vitorpamplona/amethyst/commons/richtext/RichTextParserTest.kt

@@ -4400,6 +4400,35 @@ class RichTextParserTest {
             }
     }
 
+    @Test
+    fun testNowhereLinkInTheMiddleOfAPost() {
+        val text = "Check out my store https://nowhr.xyz/s#bYxNC4JAEEDRX7LbpcsirR9F1MW0jRDLPsEOMZaHinJTCzOl right now"
+        val state = RichTextParser().parseText(text, EmptyTagList, null)
+        val nowhere = state.paragraphs.flatMap { it.words }.firstOrNull { it is NowhereLinkSegment } as? NowhereLinkSegment
+        assertEquals("https://nowhr.xyz/s#bYxNC4JAEEDRX7LbpcsirR9F1MW0jRDLPsEOMZaHinJTCzOl", nowhere?.segmentText)
+        assertEquals("nowhr.xyz", nowhere?.host)
+        assertEquals("s", nowhere?.tool)
+    }
+
+    @Test
+    fun testHostedNowhereSchemelessLink() {
+        val text = "see hostednowhere.com/m#bYxNAB end"
+        val state = RichTextParser().parseText(text, EmptyTagList, null)
+        val nowhere = state.paragraphs.flatMap { it.words }.firstOrNull { it is NowhereLinkSegment } as? NowhereLinkSegment
+        assertEquals("hostednowhere.com/m#bYxNAB", nowhere?.segmentText)
+        assertEquals("hostednowhere.com", nowhere?.host)
+        assertEquals("m", nowhere?.tool)
+    }
+
+    @Test
+    fun testPlainNowhereHostWithoutFragmentStaysAsLink() {
+        // No fragment => not a nowhere site, fall through to LinkSegment.
+        val text = "Visit https://hostednowhere.com/manage to manage"
+        val state = RichTextParser().parseText(text, EmptyTagList, null)
+        val nowhere = state.paragraphs.flatMap { it.words }.firstOrNull { it is NowhereLinkSegment }
+        assertEquals(null, nowhere)
+    }
+
     private fun printStateForDebug(state: RichTextViewerState) {
         state.paragraphs.forEach { paragraph ->
             paragraph.words.forEach { seg ->