fix: key search result rows by dictionary, offset and word

Paging result rows had no keys and were matched by position: appended
pages and query diffs could not reuse row state. Keys derived from
dictionaryPath+offset+word are stable per row, and the paging source
collapses duplicate entries for one dictionary card: case and diacritic
alias variants of a headword share the normalized word, so entries are
deduplicated by dictionaryPath+word+offset before emitting.

app/src/main/java/com/example/research/data/paging/IndexEntryPagingSource.kt

@@ -46,9 +46,8 @@ class IndexEntryPagingSource(
 
     private data class EmittedKey(
         val dictPosition: Int,
-        val originalWord: String,
-        val offset: Long,
-        val length: Int
+        val word: String,
+        val offset: Long
     )
 
     private val emittedArticles = HashSet<EmittedKey>()
@@ -103,6 +102,7 @@ class IndexEntryPagingSource(
                 val normalizedQuery = query.sanitizeQuery().lowercase().trim()
                 val ranked = rawResults.map { it.second }
                     .rankBySearchRelevance(SearchRankingContext(normalizedQuery))
+                    .distinctBy { Triple(it.dictionaryPath, it.word, it.offset.value) }
 
                 rawResults.forEach { (position, entry) -> emittedArticles.add(entry.emittedKey(position)) }
 
@@ -184,7 +184,7 @@ class IndexEntryPagingSource(
     }
 
     private fun IndexEntry.emittedKey(dictPosition: Int) =
-        EmittedKey(dictPosition, originalWord, offset.value, length.value)
+        EmittedKey(dictPosition, word, offset.value)
 
     override fun getRefreshKey(state: PagingState<TailKey, IndexEntry>): TailKey? {
         return null

app/src/main/java/com/example/research/ui/main/components/SearchResultsList.kt

@@ -41,6 +41,7 @@ fun SearchResultsList(
     ) {
         items(
             count = results.itemCount,
+            key = results.itemKey { "${it.dictionaryPath}:${it.offset.value}:${it.word}" },
             contentType = results.itemContentType { "search_result" }
         ) { index ->
             results[index]?.let { entry ->