refactor: simplify NostrClient API for beginner-friendliness

Comprehensive rename of the NostrClient relay infrastructure to use
intuitive, self-documenting names instead of protocol-level jargon.

Interface/class renames:
- INostrClient → NostrClient (interface)
- NostrClient → DefaultNostrClient (implementation)
- IRequestListener → SubscriptionListener
- IRelayClientListener → RelayConnectionListener
- IOpenNostrRequest → SubscriptionHandle
- NostrClientStaticReq → StaticSubscription
- NostrClientDynamicReq → DynamicSubscription

Method renames:
- openReqSubscription() → subscribe()
- close(subId) → unsubscribe(subId)
- send() → publish()
- queryCount() → count()
- subscribe/unsubscribe(listener) → addConnectionListener/removeConnectionListener
- renewFilters() → syncFilters()

Callback renames:
- onEose → onCaughtUp
- isLive → isRealTime
- onStartReq → onSubscriptionStarted
- onCloseReq → onSubscriptionClosed

Extension function renames:
- query() → fetchAll()
- downloadFirstEvent() → fetchFirst()
- req() → subscribe()
- reqAsFlow() → subscribeAsFlow()
- reqUntilEoseAsFlow() → fetchAsFlow()
- sendAndWaitForResponse() → publishAndConfirm()
- queryCountSuspend() → count()
- queryCountMergedHll() → countMerged()
- reqBypassingRelayLimits() → fetchAllPages()
- updateFilter() → refresh() on SubscriptionHandle

https://claude.ai/code/session_01JPcYCcRx5eZN4GvgGxGwbf

quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/nip46RemoteSigner/signer/NostrSignerRemoteIsolationTest.kt

@@ -22,9 +22,9 @@ package com.vitorpamplona.quartz.nip46RemoteSigner.signer
 
 import com.vitorpamplona.quartz.nip01Core.core.Event
 import com.vitorpamplona.quartz.nip01Core.crypto.KeyPair
-import com.vitorpamplona.quartz.nip01Core.relay.client.INostrClient
-import com.vitorpamplona.quartz.nip01Core.relay.client.listeners.IRelayClientListener
-import com.vitorpamplona.quartz.nip01Core.relay.client.reqs.IRequestListener
+import com.vitorpamplona.quartz.nip01Core.relay.client.NostrClient
+import com.vitorpamplona.quartz.nip01Core.relay.client.listeners.RelayConnectionListener
+import com.vitorpamplona.quartz.nip01Core.relay.client.reqs.SubscriptionListener
 import com.vitorpamplona.quartz.nip01Core.relay.client.single.IRelayClient
 import com.vitorpamplona.quartz.nip01Core.relay.filters.Filter
 import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
@@ -37,10 +37,10 @@ import kotlin.test.assertNotNull
 import kotlin.test.assertTrue
 
 /**
- * INostrClient that records openReqSubscription calls for verification.
+ * NostrClient that records subscribe calls for verification.
  * Used instead of mockk since commonTest doesn't have mockk.
  */
-private class TrackingNostrClient : INostrClient {
+private class TrackingNostrClient : NostrClient {
     data class SubscriptionRecord(
         val subId: String,
         val filters: Map<NormalizedRelayUrl, List<Filter>>,
@@ -64,33 +64,33 @@ private class TrackingNostrClient : INostrClient {
 
     override fun isActive() = false
 
-    override fun renewFilters(relay: IRelayClient) {}
+    override fun syncFilters(relay: IRelayClient) {}
 
-    override fun openReqSubscription(
+    override fun subscribe(
         subId: String,
         filters: Map<NormalizedRelayUrl, List<Filter>>,
-        listener: IRequestListener?,
+        listener: SubscriptionListener?,
     ) {
         subscriptions.add(SubscriptionRecord(subId, filters))
     }
 
-    override fun queryCount(
+    override fun count(
         subId: String,
         filters: Map<NormalizedRelayUrl, List<Filter>>,
     ) {}
 
-    override fun close(subId: String) {}
+    override fun unsubscribe(subId: String) {}
 
-    override fun send(
+    override fun publish(
         event: Event,
         relayList: Set<NormalizedRelayUrl>,
     ) {
         sentEvents.add(event to relayList)
     }
 
-    override fun subscribe(listener: IRelayClientListener) {}
+    override fun addConnectionListener(listener: RelayConnectionListener) {}
 
-    override fun unsubscribe(listener: IRelayClientListener) {}
+    override fun removeConnectionListener(listener: RelayConnectionListener) {}
 
     override fun getReqFiltersOrNull(subId: String): Map<NormalizedRelayUrl, List<Filter>>? = null
 
@@ -120,7 +120,7 @@ class NostrSignerRemoteIsolationTest {
         val trackingClient = TrackingNostrClient()
         val ephemeralSigner = NostrSignerInternal(KeyPair())
 
-        // Construction triggers client.req() which calls openReqSubscription
+        // Construction triggers client.subscribe() which calls subscribe
         NostrSignerRemote(
             signer = ephemeralSigner,
             remotePubkey = validHex,