refactor(spring-boot-starter): rename directory to match contrib convention

contrib/adk-spring-boot-starter/ -> contrib/spring-boot-starter/

The previous directory name carried an extra 'adk-' prefix that none of
the other contrib modules use. Every other contrib follows
'contrib/<short-name>/' with the Maven artifactId 'google-adk-<short-name>':

  contrib/spring-ai/                    -> google-adk-spring-ai
  contrib/langchain4j/                  -> google-adk-langchain4j
  contrib/firestore-session-service/    -> google-adk-firestore-session-service
  contrib/planners/                     -> google-adk-planners

Aligning the starter to the same shape:

  contrib/spring-boot-starter/          -> google-adk-spring-boot-starter

Updated:
- Root pom.xml <modules> entry to point at the new path.
- Sample README link to the starter README.
- Linter-driven reformatting on the two sample source files
  (AgentConfig, AgentService) carried in from the build.

Author: mekkiamiri

contrib/samples/spring-boot-adk-template/README.md

@@ -32,7 +32,7 @@ mvn -pl contrib/samples/spring-boot-adk-template -am spring-boot:run
 
 `src/main/resources/application.yaml` shows the full property surface as comments. The defaults give an all-in-memory configuration with no GCP credentials required — switch backends by uncommenting the relevant blocks (`adk.session.type=VERTEX_AI`, `adk.session.type=FIRESTORE`, `adk.artifacts.gcs-enabled=true`, etc.).
 
-See the [starter README](../../adk-spring-boot-starter/README.md) for the full property reference.
+See the [starter README](../../spring-boot-starter/README.md) for the full property reference.
 
 ## Use Spring AI as the LLM substrate (optional)
 

contrib/samples/spring-boot-adk-template/src/main/java/com/example/springbootadktemplate/AgentService.java

@@ -7,16 +7,18 @@
 @Service
 public class AgentService {
 
-    private final Runner runner;
-    private final LlmAgent agent;
+  private final Runner runner;
+  private final LlmAgent agent;
 
-    public AgentService(Runner runner, LlmAgent agent) {
-        this.runner = runner;
-        this.agent = agent;
-    }
+  public AgentService(Runner runner, LlmAgent agent) {
+    this.runner = runner;
+    this.agent = agent;
+  }
 
-    public String getAgentInfo() {
-        return "Agent created: " + agent.getClass().getSimpleName() +
-                ", Runner: " + runner.getClass().getSimpleName();
-    }
+  public String getAgentInfo() {
+    return "Agent created: "
+        + agent.getClass().getSimpleName()
+        + ", Runner: "
+        + runner.getClass().getSimpleName();
+  }
 }

contrib/samples/spring-boot-adk-template/src/main/java/com/example/springbootadktemplate/config/AgentConfig.java

@@ -19,8 +19,8 @@
  * Sample agent topology — defines a root LlmAgent and packages it into an App.
  *
  * <p>The starter provides {@code Runner}, {@code BaseSessionService}, {@code BaseArtifactService},
- * and {@code RunConfig} automatically — this configuration only declares the user-specific
- * agent topology.
+ * and {@code RunConfig} automatically — this configuration only declares the user-specific agent
+ * topology.
  */
 @Configuration
 public class AgentConfig {