search: update exploration logic and UI empty states

CLAUDE.md

@@ -158,6 +158,8 @@ Custom Gradle plugins in `build-logic/convention/` standardize module setup:
 - **Shizuku (Android):** Optional silent install via `ShizukuProvider` (registered in AndroidManifest). Requires Shizuku app running with ADB or root. AIDL service passes APK via `ParcelFileDescriptor` to `pm install -S`. Falls back to standard installer on failure.
 - **Gradle properties:** Config cache enabled, build cache enabled, 4GB Gradle heap, 3GB Kotlin daemon heap
 - **Code style:** Official Kotlin style (`kotlin.code.style=official`)
+- **Desktop logs:** `CrashReporter` (installed as the first line of `DesktopApp.main`) tees `System.out`/`System.err` to a rotating `session.log` and writes `crash-<timestamp>.log` on uncaught exceptions. Paths: `~/Library/Logs/GitHub-Store/` (macOS), `%LOCALAPPDATA%/GitHub-Store/logs/` (Windows), `$XDG_STATE_HOME/GitHub-Store/logs/` (Linux). Android uses Logcat — no CrashReporter.
+- **`X-GitHub-Token` header:** Forwarded to the backend *only* on `/v1/search` and `/v1/search/explore` (so the backend's live GitHub passthrough runs under the user's own 5000/hr quota). Sourced from `TokenStore.currentToken()` via `BackendApiClient.currentUserGithubToken()` — the helper is `private` so other endpoints can't leak it accidentally. Never sent on other endpoints (`/v1/categories`, `/v1/topics`, `/v1/repo`, `/v1/events`), never logged (no Ktor `Logging` plugin installed).
 
 ## Coding Conventions
 

core/data/src/commonMain/kotlin/zed/rainxch/core/data/dto/BackendSearchResponse.kt

@@ -8,4 +8,5 @@ data class BackendSearchResponse(
     val totalHits: Int,
     val processingTimeMs: Int,
     val source: String? = null,
+    val passthroughAttempted: Boolean? = null,
 )

core/data/src/commonMain/kotlin/zed/rainxch/core/data/logging/KermitLogger.kt

@@ -22,4 +22,29 @@ object KermitLogger : GitHubStoreLogger {
     ) {
         Logger.e(message, throwable)
     }
+
+    override fun withTag(tag: String): GitHubStoreLogger = TaggedKermitLogger(Logger.withTag(tag))
+}
+
+private class TaggedKermitLogger(private val delegate: Logger) : GitHubStoreLogger {
+    override fun debug(message: String) {
+        delegate.d(message)
+    }
+
+    override fun info(message: String) {
+        delegate.i(message)
+    }
+
+    override fun warn(message: String) {
+        delegate.w(message)
+    }
+
+    override fun error(
+        message: String,
+        throwable: Throwable?,
+    ) {
+        delegate.e(message, throwable)
+    }
+
+    override fun withTag(tag: String): GitHubStoreLogger = TaggedKermitLogger(delegate.withTag(tag))
 }

core/data/src/commonMain/kotlin/zed/rainxch/core/data/network/BackendApiClient.kt

@@ -140,7 +140,12 @@ class BackendApiClient(
                 parameter("q", query)
                 if (platform != null) parameter("platform", platform)
                 parameter("page", page)
-                timeout { requestTimeoutMillis = 20_000 }
+
+                timeout {
+                    requestTimeoutMillis = 30_000
+                    socketTimeoutMillis = 30_000
+                }
+
                 if (token != null) header(X_GITHUB_TOKEN_HEADER, token)
             }
             if (response.status.isSuccess()) {

core/domain/src/commonMain/kotlin/zed/rainxch/core/domain/logging/GitHubStoreLogger.kt

@@ -11,4 +11,6 @@ interface GitHubStoreLogger {
         message: String,
         throwable: Throwable? = null,
     )
+
+    fun withTag(tag: String): GitHubStoreLogger = this
 }

core/domain/src/commonMain/kotlin/zed/rainxch/core/domain/model/PaginatedDiscoveryRepositories.kt

@@ -8,4 +8,5 @@ data class PaginatedDiscoveryRepositories(
     val hasMore: Boolean,
     val nextPageIndex: Int,
     val totalCount: Int? = null,
+    val passthroughAttempted: Boolean? = null,
 )

feature/search/data/src/commonMain/kotlin/zed/rainxch/search/data/repository/SearchRepositoryImpl.kt

@@ -147,6 +147,7 @@ class SearchRepositoryImpl(
                 hasMore = hasMore,
                 nextPageIndex = page + 1,
                 totalCount = searchResponse.totalHits,
+                passthroughAttempted = searchResponse.passthroughAttempted,
             )
         }
     }

feature/search/presentation/src/commonMain/kotlin/zed/rainxch/search/presentation/SearchRoot.kt

@@ -541,6 +541,35 @@ fun SearchScreen(
                     }
                 }
 
+                if (!state.isLoading &&
+                    !state.isLoadingMore &&
+                    state.errorMessage == null &&
+                    state.repositories.isEmpty() &&
+                    state.query.isNotBlank() &&
+                    !state.hasMorePages
+                ) {
+                    Box(
+                        modifier = Modifier.fillMaxSize(),
+                        contentAlignment = Alignment.Center,
+                    ) {
+                        Column(horizontalAlignment = Alignment.CenterHorizontally) {
+                            Text(text = stringResource(Res.string.no_repositories_found))
+
+                            // Backend already did its own passthrough and still found
+                            // nothing — don't tease a manual explore that would just
+                            // redo the same work. Any other case (false / null for
+                            // older backends) keeps the CTA.
+                            if (state.passthroughAttempted != true) {
+                                Spacer(Modifier.height(8.dp))
+                                ExploreFromGithubButton(
+                                    status = state.exploreStatus,
+                                    onExplore = { onAction(SearchAction.ExploreFromGithub) },
+                                )
+                            }
+                        }
+                    }
+                }
+
                 if (state.visibleRepos.isNotEmpty()) {
                     val isScrollbarEnabled = LocalScrollbarEnabled.current
                     ScrollbarContainer(

feature/search/presentation/src/commonMain/kotlin/zed/rainxch/search/presentation/SearchState.kt

@@ -33,6 +33,7 @@ data class SearchState(
     val autoDetectClipboardEnabled: Boolean = true,
     val recentSearches: ImmutableList<String> = persistentListOf(),
     val exploreStatus: ExploreStatus = ExploreStatus.IDLE,
+    val passthroughAttempted: Boolean? = null,
 ) {
     enum class ExploreStatus {
         IDLE,

feature/search/presentation/src/commonMain/kotlin/zed/rainxch/search/presentation/SearchViewModel.kt

@@ -39,7 +39,6 @@ import zed.rainxch.githubstore.core.presentation.res.failed_to_share_link
 import zed.rainxch.githubstore.core.presentation.res.link_copied_to_clipboard
 import zed.rainxch.githubstore.core.presentation.res.no_github_link_in_clipboard
 import zed.rainxch.githubstore.core.presentation.res.explore_error
-import zed.rainxch.githubstore.core.presentation.res.no_repositories_found
 import zed.rainxch.githubstore.core.presentation.res.search_failed
 import zed.rainxch.search.presentation.mappers.toDomain
 import zed.rainxch.search.presentation.utils.isEntirelyGithubUrls
@@ -66,6 +65,8 @@ class SearchViewModel(
     private var explorePage = 1
     private var lastExploreQuery = ""
 
+    private val exploreLog = logger.withTag("SearchExplore")
+
     companion object {
         private const val MIN_QUERY_LENGTH = 3
     }
@@ -295,7 +296,12 @@ class SearchViewModel(
             currentPage = 1
             explorePage = 1
             lastExploreQuery = query
-            _state.update { it.copy(exploreStatus = SearchState.ExploreStatus.IDLE) }
+            _state.update {
+                it.copy(
+                    exploreStatus = SearchState.ExploreStatus.IDLE,
+                    passthroughAttempted = null,
+                )
+            }
         }
 
         currentSearchJob =
@@ -312,6 +318,8 @@ class SearchViewModel(
                                 it.repositories
                             },
                         totalCount = if (isInitial) null else it.totalCount,
+                        passthroughAttempted =
+                            if (isInitial) null else it.passthroughAttempted,
                     )
                 }
 
@@ -390,12 +398,8 @@ class SearchViewModel(
                                     repositories = allRepos,
                                     hasMorePages = paginatedRepos.hasMore,
                                     totalCount = allRepos.size,
-                                    errorMessage =
-                                        if (allRepos.isEmpty() && !paginatedRepos.hasMore) {
-                                            getString(Res.string.no_repositories_found)
-                                        } else {
-                                            null
-                                        },
+                                    errorMessage = null,
+                                    passthroughAttempted = paginatedRepos.passthroughAttempted,
                                 )
                             }
                         }
@@ -682,10 +686,27 @@ class SearchViewModel(
 
     private fun performExplore() {
         val query = _state.value.query.trim()
-        if (query.isBlank() || _state.value.exploreStatus == SearchState.ExploreStatus.LOADING) return
+        val platformUi = _state.value.selectedSearchPlatform
+        val prevStatus = _state.value.exploreStatus
+
+        exploreLog.debug(
+            "click: query='$query' platform=$platformUi " +
+                "page=$explorePage lastQuery='$lastExploreQuery' status=$prevStatus",
+        )
+
+        if (query.isBlank()) {
+            exploreLog.debug("skipped: query is blank")
+            return
+        }
+        if (prevStatus == SearchState.ExploreStatus.LOADING) {
+            exploreLog.debug("skipped: already LOADING")
+            return
+        }
 
-        // Reset page if query changed
         if (query != lastExploreQuery) {
+            exploreLog.debug(
+                "query changed ('$lastExploreQuery' -> '$query'); resetting page to 1",
+            )
             explorePage = 1
             lastExploreQuery = query
         }
@@ -696,24 +717,40 @@ class SearchViewModel(
             try {
                 val exploreResult = searchRepository.exploreFromGithub(
                     query = query,
-                    platform = _state.value.selectedSearchPlatform.toDomain(),
+                    platform = platformUi.toDomain(),
                     page = explorePage,
                 )
+                val existingCount = _state.value.repositories.size
+                exploreLog.debug(
+                    "response: items=${exploreResult.repos.size} " +
+                        "returnedPage=${exploreResult.page} hasMore=${exploreResult.hasMore} " +
+                        "existingVisible=$existingCount",
+                )
 
-                if (exploreResult.repos.isEmpty() || !exploreResult.hasMore) {
-                    if (exploreResult.repos.isNotEmpty()) {
-                        appendExploreResults(exploreResult.repos)
-                    }
-                    _state.update { it.copy(exploreStatus = SearchState.ExploreStatus.EXHAUSTED) }
-                } else {
+                val before = _state.value.repositories.size
+                if (exploreResult.repos.isNotEmpty()) {
                     appendExploreResults(exploreResult.repos)
+                }
+                val added = _state.value.repositories.size - before
+                val dupes = exploreResult.repos.size - added
+
+                if (exploreResult.hasMore) {
                     explorePage++
+                    exploreLog.debug(
+                        "-> IDLE: appended=$added dupes=$dupes nextPage=$explorePage",
+                    )
                     _state.update { it.copy(exploreStatus = SearchState.ExploreStatus.IDLE) }
+                } else {
+                    exploreLog.debug(
+                        "-> EXHAUSTED: appended=$added dupes=$dupes " +
+                            "rawItems=${exploreResult.repos.size}",
+                    )
+                    _state.update { it.copy(exploreStatus = SearchState.ExploreStatus.EXHAUSTED) }
                 }
             } catch (e: CancellationException) {
                 throw e
             } catch (e: Exception) {
-                logger.error("Explore failed: ${e.message}")
+                exploreLog.error("failed: ${e::class.simpleName}: ${e.message}", e)
                 _state.update { it.copy(exploreStatus = SearchState.ExploreStatus.IDLE) }
                 _events.send(SearchEvent.OnMessage(getString(Res.string.explore_error)))
             }