server: S5 memoize listSessionSummaries + S6 Main.kt hygiene

S5 — GET /sessions re-read + re-projected every session's full log on every
call. Cache keyed on eventStore.lastGlobalSequence(); volatile pair-swap,
no lock — any append bumps the seq so a stale read is impossible.

S6 — close research + health-probe HttpClients via shutdown hook; log the
real configured host:port (was hardcoded 8080) and bind to it; System.err
-> SLF4J; WARN at startup on non-loopback bind (unauthenticated surface).
resolveApiKey precedence item N/A — no such code exists.

Both verified green in isolated worktrees (226 pass). Full local build
currently blocked by an unrelated concurrent core:config edit.

apps/server/src/main/kotlin/com/correx/apps/server/Main.kt

@@ -109,9 +109,10 @@ import java.nio.file.Paths
 
 private val log = LoggerFactory.getLogger("com.correx.apps.server.Main")
 
+private val loopbackHosts = setOf("localhost", "127.0.0.1", "::1")
+
 fun main() {
     log.info("=== correx server starting ===")
-    log.info("  port         : 8080")
     val artifactStore = InfrastructureModule.createArtifactStore()
     val eventStore = LoggingEventStore(InfrastructureModule.createEventStore(artifactStore))
 
@@ -218,16 +219,19 @@ fun main() {
     val workingDir = explicitWorkingDir ?: workspaceRoot
     // One shared HTTP client backs both the default and per-workspace registries' research tools
     // (web_search/web_fetch). Built only when research is enabled, so the static path stays offline.
+    // Lives for the process lifetime (shared across requests), so it's closed via shutdown hook
+    // below rather than `.use { }`.
+    val researchHttpClient = if (toolsConfig.research.enabled) {
+        io.ktor.client.HttpClient(io.ktor.client.engine.cio.CIO)
+    } else {
+        null
+    }
     val researchToolConfig = com.correx.infrastructure.tools.ResearchToolConfig(
         enabled = toolsConfig.research.enabled,
         searxngUrl = toolsConfig.research.searxngUrl,
         maxResults = toolsConfig.research.maxResults,
         maxFetchBytes = toolsConfig.research.maxFetchBytes,
-        httpClient = if (toolsConfig.research.enabled) {
-            io.ktor.client.HttpClient(io.ktor.client.engine.cio.CIO)
-        } else {
-            null
-        },
+        httpClient = researchHttpClient,
     )
     // Agents create/update/delete tasks through the tool system (tier-gated like any tool);
     // the service appends to the same event log. Project is derived from the task id prefix.
@@ -534,6 +538,8 @@ fun main() {
     )
     // observability-spec §4: continuous health watch. Seed the monitor's last-status from the
     // recorded system-session events so a restart doesn't re-emit a degraded already in the log.
+    // healthProbeHttpClient lives for the process lifetime; closed via shutdown hook below.
+    var healthProbeHttpClient: io.ktor.client.HttpClient? = null
     val healthMonitor = correxConfig.health.let { hc ->
         if (!hc.enabled) {
             null
@@ -542,6 +548,7 @@ fun main() {
             val seeded = DefaultEventReplayer(eventStore, com.correx.apps.server.health.HealthProjection())
                 .rebuild(com.correx.apps.server.health.SYSTEM_SESSION)
                 .subjects.mapValues { it.value.status }
+            healthProbeHttpClient = io.ktor.client.HttpClient(io.ktor.client.engine.cio.CIO)
             com.correx.apps.server.health.HealthMonitor(
                 eventStore = eventStore,
                 probes = listOfNotNull(
@@ -552,7 +559,7 @@ fun main() {
                     ),
                     com.correx.apps.server.health.LlamaServerHealthProbe(
                         llamaBaseUrl = llamaBaseUrl,
-                        httpClient = io.ktor.client.HttpClient(io.ktor.client.engine.cio.CIO),
+                        httpClient = healthProbeHttpClient!!,
                         eventStore = eventStore,
                         livenessTimeoutMs = hc.llamaLivenessTimeoutMs,
                         tpsWarnBelow = hc.llamaTpsWarnBelow,
@@ -567,6 +574,12 @@ fun main() {
             )
         }
     }
+    Runtime.getRuntime().addShutdownHook(
+        Thread {
+            researchHttpClient?.close()
+            healthProbeHttpClient?.close()
+        },
+    )
     val module = ServerModule(
         orchestrator = orchestrator,
         eventStore = eventStore,
@@ -609,7 +622,16 @@ fun main() {
     module.start()
     log.info("==============================")
 
-    embeddedServer(Netty, port = correxConfig.server.port, host = correxConfig.server.host) {
+    val serverConfig = correxConfig.server
+    log.info("  host:port    : {}:{}", serverConfig.host, serverConfig.port)
+    if (serverConfig.host !in loopbackHosts) {
+        log.warn(
+            "Server host '{}' is not loopback — the unauthenticated HTTP/WS surface is exposed to the network",
+            serverConfig.host,
+        )
+    }
+
+    embeddedServer(Netty, host = serverConfig.host, port = serverConfig.port) {
         configureServer(module)
     }.start(wait = true)
 }
@@ -674,9 +696,7 @@ private fun loadConfigArtifactKinds(config: CorrexConfig): List<ArtifactKind> {
         val schema = runCatching {
             Json.decodeFromString(JsonSchema.serializer(), Files.readString(schemaPath))
         }.getOrElse { e ->
-            System.err.println(
-                "Warning: artifact kind '${decl.id}' schema '$schemaPath' failed to load: ${e.message}",
-            )
+            log.warn("artifact kind '{}' schema '{}' failed to load: {}", decl.id, schemaPath, e.message)
             return@mapNotNull null
         }
         ConfigArtifactKind(id = decl.id, schema = schema, llmEmitted = decl.llmEmitted)

apps/server/src/main/kotlin/com/correx/apps/server/ServerModule.kt

@@ -624,13 +624,25 @@ class ServerModule(
 
     private val sessionSummaryProjector = SessionSummaryProjector()
 
-    fun listSessionSummaries(): List<SessionSummary> =
-        eventStore.allSessionIds()
+    // ponytail: memoized on lastGlobalSequence — GET /sessions was re-reading + re-projecting every
+    // session's full log on every call (S5). Any new event anywhere bumps the global sequence, so a
+    // stale cache is impossible: a mismatch always forces a full recompute. Volatile pair-swap is
+    // enough here (no lock) — worst case under a race is one redundant recompute, never a stale read.
+    @Volatile
+    private var sessionSummaryCache: Pair<Long, List<SessionSummary>>? = null
+
+    suspend fun listSessionSummaries(): List<SessionSummary> {
+        val currentSeq = eventStore.lastGlobalSequence()
+        sessionSummaryCache?.let { (seq, summaries) -> if (seq == currentSeq) return summaries }
+        val summaries = eventStore.allSessionIds()
             // The system session carries global health events, not a user workflow — hide it.
             .filter { it != com.correx.apps.server.health.SYSTEM_SESSION }
             .map { sessionId ->
                 sessionSummaryProjector.project(sessionId, eventStore.readFrom(sessionId, fromSequence = 0L))
             }
+        sessionSummaryCache = currentSeq to summaries
+        return summaries
+    }
 
     private fun preRegisterPendingApprovals() {
         val projector = ApprovalProjector(DefaultApprovalReducer())