feat(highlights): add article highlights and note-taking system

Phase 1: HighlightData model + DesktopHighlightStore (Preferences-based)
Phase 2: Text selection highlight via Cmd+H/Cmd+Shift+H, inline bold/italic
         rendering, HighlightAnnotationDialog, SelectionContainer wrapping
Phase 3: MyHighlightsScreen with grouped view, HighlightPublishAction for
         NIP-84 (kind 9802), deck/sidebar/menu wiring

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/compose/markdown/RenderMarkdown.kt

@@ -42,10 +42,27 @@ fun RenderMarkdown(
     onLinkClick: (String) -> Unit,
     modifier: Modifier = Modifier,
     fontScale: Float = 1.0f,
+    highlightedTexts: List<String> = emptyList(),
 ) {
+    val processedContent =
+        remember(content, highlightedTexts) {
+            if (highlightedTexts.isEmpty()) {
+                content
+            } else {
+                var result = content
+                highlightedTexts.sortedByDescending { it.length }.forEach { text ->
+                    val idx = result.indexOf(text)
+                    if (idx >= 0) {
+                        result = result.replaceFirst(text, "***$text***")
+                    }
+                }
+                result
+            }
+        }
+
     val astNode =
-        remember(content) {
-            CommonmarkAstNodeParser(CommonMarkdownParseOptions.MarkdownWithLinks).parse(content)
+        remember(processedContent) {
+            CommonmarkAstNodeParser(CommonMarkdownParseOptions.MarkdownWithLinks).parse(processedContent)
         }
 
     val uriHandler =

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/model/highlights/HighlightData.kt

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.model.highlights
+
+data class HighlightData(
+    val id: String,
+    val text: String,
+    val note: String? = null,
+    val articleAddressTag: String,
+    val articleTitle: String? = null,
+    val createdAt: Long,
+    val published: Boolean = false,
+    val eventId: String? = null,
+)