fix(mcp): upgrade Spring Boot to 4.0.0 in brave-chatbot

[kushalsharma1218]

Resolves ClassNotFoundException for RetryTemplate (#86) caused by Spring AI 2.0.0-SNAPSHOT requirements.

[kushalsharma1218]

1. Problem
   Running the brave-chatbot with Spring Boot 3.4.5 caused a startup failure due to a dependency conflict with Spring AI 2.0.0-SNAPSHOT, which requires classes from newer Spring libraries.

Reproduction Error:
java
java.lang.IllegalStateException: Error processing condition on org.springframework.ai.retry.autoconfigure.SpringAiRetryAutoConfiguration.retryTemplate
Caused by: java.lang.ClassNotFoundException: org.springframework.core.retry.RetryTemplate

2. The Minimal Fix
   Upgraded the spring-boot-starter-parent version from 3.4.5 to 4.0.0 specifically in the brave-chatbot module. This aligns the transitive dependencies and provides the required RetryTemplate class.

Change in -> pom.xml

<parent>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-parent</artifactId>
-    <version>3.4.5</version>
+    <version>4.0.0</version>
     <relativePath /> <!-- lookup parent from repository -->
 </parent>

3. Verification (The Success)
   After the upgrade, the application starts successfully and initializes the MCP client without errors.

Successful Startup Log:

.   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v4.0.0)
... INFO ... o.s.ai.mcp.samples.brave.Application     : Starting Application...
... INFO ... i.m.c.transport.StdioClientTransport     : MCP server started

[kushalsharma1218]

@joshlong @claude @trevormarshall @sdeleuze @tzolov please check this