feat(mcp): Refactor MCP server API to use Specification pattern

- Rename Registration classes to Specification (SyncToolRegistration → SyncToolSpecification)
- Update transport classes to use Provider suffix (WebFluxSseServerTransport → WebFluxSseServerTransportProvider)
- Add exchange parameter to handler methods for better context passing
- Introduce McpBackwardCompatibility class to maintain backward compatibility
- Update MCP Server documentation to reflect new API patterns
- Add tests for backward compatibility
- Update mcp version to 0.8.0
- Add mcp 0.8.0 breaking change note-

The changes align with the MCP specification evolution while maintaining backward compatibility through deprecated APIs.

refactor: Extract MCP tool callback configuration into separate auto-configuration

Extracts the MCP tool callback functionality from McpClientAutoConfiguration into a
new dedicated McpToolCallbackAutoConfiguration that is disabled by default.

- Created new McpToolCallbackAutoConfiguration class that handles tool callback registration
- Made tool callbacks opt-in by requiring explicit configuration with spring.ai.mcp.client.toolcallback.enabled=true
- Removed deprecated tool callback methods from McpClientAutoConfiguration
- Updated ClientMcpTransport references to McpClientTransport to align with MCP library changes
- Added tests for the new auto-configuration and its conditions

refactor: standardize tool names to use underscores instead of hyphens

- Change separator in McpToolUtils.prefixedToolName from hyphen to underscore
- Add conversion of any remaining hyphens to underscores in formatted tool names
- Update affected tests to reflect the new naming convention
- Add comprehensive tests for McpToolUtils.prefixedToolName method
- Add integration test for payment transaction tools with Vertex AI Gemini

Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>

pom.xml

@@ -291,7 +291,7 @@
 		<okhttp3.version>4.12.0</okhttp3.version>
 
 		<!-- MCP-->
-		<mcp.sdk.version>0.8.0-SNAPSHOT</mcp.sdk.version>
+		<mcp.sdk.version>0.8.0</mcp.sdk.version>
 
 		<!-- plugin versions -->
 		<antlr.version>4.13.1</antlr.version>