refactor: rename quartz-relay module to geode

The relay implementation now stands as its own module. Fitting brand
for a Nostr relay shipped alongside the Quartz library — a geode is a
rock that holds quartz inside.

- Rename module directory quartz-relay/ -> geode/.
- Rename Gradle module path :quartz-relay -> :geode (settings.gradle).
- Rename Kotlin package com.vitorpamplona.quartz.relay -> com.vitorpamplona.geode.
- Rename application name + main class binding to match.
- Update the relay's NIP-11 advertised name to "geode" and the
  software URL to /tree/main/geode. Test asserting the doc updated.
- Refresh comments / Main.kt usage line / config.example.toml header.
- Update consumers: quartz/build.gradle.kts dependency path, and
  quartz NostrClient tests that import the in-process RelayHub.

geode/build.gradle.kts

@@ -0,0 +1,70 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
+plugins {
+    alias(libs.plugins.jetbrainsKotlinJvm)
+    alias(libs.plugins.serialization)
+    application
+}
+
+application {
+    mainClass.set("com.vitorpamplona.geode.MainKt")
+    applicationName = "geode"
+}
+
+kotlin {
+    jvmToolchain(21)
+    compilerOptions {
+        jvmTarget.set(JvmTarget.JVM_21)
+    }
+}
+
+sourceSets {
+    main {
+        kotlin.srcDir("src/main/kotlin")
+    }
+    test {
+        kotlin.srcDir("src/test/kotlin")
+    }
+}
+
+tasks.withType<Test>().configureEach {
+    // Forward `-DrunLoadBenchmark=true` to the test JVM so the
+    // perf.LoadBenchmark tests opt in. Off by default — load tests
+    // are noisy and slow.
+    systemProperty("runLoadBenchmark", System.getProperty("runLoadBenchmark") ?: "false")
+    // Show println output from test JVM so the benchmark numbers are
+    // actually visible without grepping the report XML.
+    testLogging {
+        showStandardStreams =
+            (System.getProperty("runLoadBenchmark") == "true")
+        events("standard_out")
+    }
+}
+
+dependencies {
+    api(project(":quartz"))
+
+    implementation(libs.kotlinx.coroutines.core)
+    implementation(libs.jackson.module.kotlin)
+    implementation(libs.kotlinx.serialization.json)
+
+    // Bundled SQLite driver — Relay's default in-memory EventStore creates
+    // an in-memory DB at runtime.
+    implementation(libs.androidx.sqlite.bundled.jvm)
+
+    // Ktor server engine + WebSocket plugin so Relay can serve real ws://
+    // traffic. CIO is the coroutine-based engine — lighter than Netty.
+    api(libs.ktor.server.core)
+    api(libs.ktor.server.cio)
+    api(libs.ktor.server.websockets)
+
+    // TOML parsing for the operator config file. Mirrors the section
+    // layout of nostr-rs-relay's config.toml so existing operators can
+    // port their configs nearly verbatim.
+    implementation(libs.fourkoma)
+
+    testImplementation(libs.kotlin.test)
+    testImplementation(libs.kotlinx.coroutines.test)
+    testImplementation(libs.secp256k1.kmp.jni.jvm)
+    testImplementation(libs.okhttp)
+}