feat: derive version from gradle.properties at build time

Replace 4 hardcoded '0.1.0-SNAPSHOT' references with BuildVersion
that reads from version.properties generated at build time.

- gradle.properties: single source of truth (now 0.3.0-SNAPSHOT)
- aceclaw-core/build.gradle.kts: generates version.properties resource
- BuildVersion.java: reads version from classpath resource
- AceClawMain, RequestRouter: use BuildVersion.version()
- Release workflow already bumps gradle.properties via git-cliff

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

aceclaw-cli/src/main/java/dev/aceclaw/cli/AceClawMain.java

@@ -31,13 +31,13 @@
 @Command(
     name = "aceclaw",
     mixinStandardHelpOptions = true,
-    version = "aceclaw 0.1.0-SNAPSHOT",
+    version = "aceclaw (version loaded at runtime)",
     description = "AI coding agent — Device as Agent",
     subcommands = { AceClawMain.DaemonCommand.class, AceClawMain.ModelsCommand.class }
 )
 public final class AceClawMain implements Runnable {
 
-    static final String VERSION = "0.1.0-SNAPSHOT";
+    static final String VERSION = dev.aceclaw.core.BuildVersion.version();
     private static final Path CODEX_AUTH_FILE = Path.of(
             System.getProperty("user.home"), ".codex", "auth.json");
 

aceclaw-core/build.gradle.kts

@@ -1,5 +1,21 @@
 // aceclaw-core: Agent loop, task planner, tool system, LLM client abstractions, agent teams
 
+// Generate version.properties from gradle.properties at build time
+tasks.register("generateVersionProperties") {
+    val outputDir = layout.buildDirectory.dir("generated/resources/version")
+    outputs.dir(outputDir)
+    doLast {
+        val dir = outputDir.get().asFile
+        dir.mkdirs()
+        dir.resolve("version.properties").writeText(
+            "# Generated by build\nversion=${project.version}\ngroup=${project.group}\n"
+        )
+    }
+}
+
+sourceSets["main"].resources.srcDir(layout.buildDirectory.dir("generated/resources/version"))
+tasks.named("processResources") { dependsOn("generateVersionProperties") }
+
 dependencies {
     api(project(":aceclaw-sdk"))
     implementation(project(":aceclaw-infra"))

aceclaw-core/src/main/java/dev/aceclaw/core/BuildVersion.java

@@ -0,0 +1,50 @@
+package dev.aceclaw.core;
+
+import java.io.InputStream;
+import java.util.Properties;
+
+/**
+ * Reads the build version from {@code version.properties} generated at build time.
+ * Single source of truth: {@code gradle.properties} → build → classpath resource.
+ */
+public final class BuildVersion {
+
+    private static final String FALLBACK = "dev";
+    private static volatile String cachedVersion;
+
+    private BuildVersion() {}
+
+    /**
+     * Returns the project version (e.g. "0.3.0-SNAPSHOT" or "0.3.0").
+     * Falls back to "dev" if the resource is missing (IDE run without build).
+     */
+    public static String version() {
+        String v = cachedVersion;
+        if (v != null) return v;
+        synchronized (BuildVersion.class) {
+            if (cachedVersion != null) return cachedVersion;
+            cachedVersion = loadVersion();
+            return cachedVersion;
+        }
+    }
+
+    /**
+     * Returns a display string like "AceClaw v0.3.0-SNAPSHOT".
+     */
+    public static String displayVersion() {
+        return "AceClaw v" + version();
+    }
+
+    private static String loadVersion() {
+        try (InputStream is = BuildVersion.class.getClassLoader()
+                .getResourceAsStream("version.properties")) {
+            if (is == null) return FALLBACK;
+            Properties props = new Properties();
+            props.load(is);
+            String v = props.getProperty("version", FALLBACK);
+            return v.isBlank() ? FALLBACK : v;
+        } catch (Exception e) {
+            return FALLBACK;
+        }
+    }
+}

aceclaw-daemon/src/main/java/dev/aceclaw/daemon/RequestRouter.java

@@ -293,7 +293,7 @@ private Object handleHealthStatus(JsonNode params) {
 
         result.put("activeSessions", sessionManager.sessionCount());
         result.put("timestamp", Instant.now().toString());
-        result.put("version", "0.1.0-SNAPSHOT");
+        result.put("version", dev.aceclaw.core.BuildVersion.version());
         var m = modelName;
         if (m != null) {
             result.put("model", m);

aceclaw-daemon/src/test/java/dev/aceclaw/daemon/DaemonIntegrationTest.java

@@ -302,7 +302,7 @@ void testHealthStatus() throws Exception {
             var result = response.get("result");
             assertThat(result.get("status").asText()).isEqualTo("healthy");
             assertThat(result.has("timestamp")).isTrue();
-            assertThat(result.get("version").asText()).isEqualTo("0.1.0-SNAPSHOT");
+            assertThat(result.get("version").asText()).isNotBlank();
         }
     }
 

gradle.properties

@@ -1,2 +1,2 @@
 group=dev.aceclaw
-version=0.1.0
+version=0.3.0-SNAPSHOT