build: modernize SDK build and fix example project structure (#21)

- Updated SDK to Java 17 using the compiler release flag to support Java records.
- Added license-checks.xml and java.header to resolve Checkstyle failures.
- Bypassed animal-sniffer-maven-plugin which was enforcing Java 8 compatibility.
- Fixed malformed example/pom.xml by moving the XML declaration to the first line.
- Reorganized example project into the standard Maven directory structure (src/main/java).
- Updated example/pom.xml to use Java 17 and :released version update tag.
- Added GitHub Action workflow to automatically verify project compilation.
- Updated .gitignore to exclude Maven target directories.

Author: meltsufin

.gitignore

@@ -50,5 +50,9 @@ crash.*.log
 *.tfvars.json
 
 # Language Specific
+<<<<<<< HEAD
 target/
+=======
+/target
+>>>>>>> 77cfd69 (build: modernize SDK build and fix example project structure (#21))
 

example/pom.xml

@@ -40,7 +40,11 @@
     <dependency>
         <groupId>com.google.cloud.mcp</groupId>
         <artifactId>mcp-toolbox-sdk-java</artifactId>
+<<<<<<< HEAD
         <version>0.1.0</version><!-- {x-version-update:mcp-toolbox-sdk-java:released} -->
+=======
+        <version>0.0.1</version><!-- {x-version-update:mcp-toolbox-sdk-java:released} -->
+>>>>>>> 77cfd69 (build: modernize SDK build and fix example project structure (#21))
     </dependency>
 
     <dependency>

pom.xml

@@ -31,7 +31,10 @@
     <description>Java client library for the Model Context Protocol (MCP) Toolbox.</description>
 
     <properties>
+<<<<<<< HEAD
         <maven.compiler.release>17</maven.compiler.release>
+=======
+>>>>>>> 77cfd69 (build: modernize SDK build and fix example project structure (#21))
         <jackson.version>2.15.2</jackson.version>
         <google.auth.version>1.23.0</google.auth.version>
         <animal.sniffer.skip>true</animal.sniffer.skip>
@@ -70,6 +73,13 @@
 
     <build>
         <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <release>17</release>
+                </configuration>
+            </plugin>
             <plugin>
                 <groupId>com.spotify.fmt</groupId>
                 <artifactId>fmt-maven-plugin</artifactId>