fix(java-spring-ai-agents): add validation starter, use non-deprecated bedrock props

- Add spring-boot-starter-validation: RC2 KB config properties are @validated,
  so the aiagent needs a Bean Validation implementation or it fails to start
- Switch to non-deprecated spring.ai.bedrock.converse.chat.* property keys
  (max-tokens, model, temperature) in app + demo-scripts

Author: Yuriy Bezsonov

apps/java-spring-ai-agents/aiagent/pom.xml

@@ -73,6 +73,11 @@
         <dependency>
             <groupId>org.springframework.ai</groupId>
             <artifactId>spring-ai-vector-store-advisor</artifactId>
+        </dependency>
+        <!-- Bean Validation implementation (Hibernate Validator) for @Validated config properties -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-validation</artifactId>
         </dependency>
 	    <!-- AgentCore Memory dependencies -->
         <dependency>

apps/java-spring-ai-agents/aiagent/src/main/resources/application.properties

@@ -6,9 +6,9 @@ logging.level.com.example.agent=DEBUG
 logging.pattern.console=%msg%n
 # Amazon Bedrock Configuration
 spring.ai.bedrock.aws.timeout=120s
-spring.ai.bedrock.converse.chat.options.max-tokens=4096
-spring.ai.bedrock.converse.chat.options.model=global.anthropic.claude-sonnet-4-6
-spring.ai.bedrock.converse.chat.options.temperature=0.7
+spring.ai.bedrock.converse.chat.max-tokens=4096
+spring.ai.bedrock.converse.chat.model=global.anthropic.claude-sonnet-4-6
+spring.ai.bedrock.converse.chat.temperature=0.7
 # AgentCore Browser - tool descriptions
 agentcore.browser.browse-url-description=Browse a web page and extract its text content. Returns the page title and body text. Use this to read and extract data from websites. For interactive sites, combine with fillForm and clickElement to navigate, then call browseUrl again to read the results.
 agentcore.browser.screenshot-description=Take a screenshot of a web page for the user to see. Does NOT return page content to you. Use browseUrl to extract data first, then takeScreenshot for visual evidence.

apps/java-spring-ai-agents/demo-scripts/01-create.sh

@@ -69,9 +69,9 @@ logging.level.com.example.agent=DEBUG
 logging.pattern.console=%msg%n
 # Amazon Bedrock Configuration
 spring.ai.bedrock.aws.timeout=120s
-spring.ai.bedrock.converse.chat.options.max-tokens=4096
-spring.ai.bedrock.converse.chat.options.model=global.anthropic.claude-sonnet-4-6
-spring.ai.bedrock.converse.chat.options.temperature=0.7
+spring.ai.bedrock.converse.chat.max-tokens=4096
+spring.ai.bedrock.converse.chat.model=global.anthropic.claude-sonnet-4-6
+spring.ai.bedrock.converse.chat.temperature=0.7
 EOF
 
 # --- Write ChatService.java ---