standardize tool metadata by adding annotation classes to sdk

Expected Behavior

It would be ideal to have Tool annotation classes (specifically Tool/ToolParam) be added to the mcp-java-sdk.

Current Behavior

Multiple, tool-specific annotations exist, the most prominent being spring's:

https://github.com/spring-projects/spring-ai/tree/main/spring-ai-model/src/main/java/org/springframework/ai/tool/annotation

These annotations (and the one interface dependency) should be a part of the java mcp-sdk itself, rather than require spring dependencies (or other emerging implementations).

Context
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It would be helpful to have Tool/ToolParam/ToolAnnotations/ToolResult annotations that are part of the java sdk, so that the MCP developer would not have to change annotations to use a different framework. Having Tool/ToolParam/ToolAnnotations/ToolResult annotations as part of the mcp itself rather than spring or any other specific framework would aid in that effort.

Beginne damit, das im Issue verlinkte Spring AI-Annotationsverzeichnis zu prüfen und dessen Tool-, ToolParam-, ToolAnnotations- und ToolResult-Annotationen mit dem aktuellen mcp-java-sdk zu vergleichen. Als abgeschlossen gilt die Arbeit, wenn das SDK frameworkunabhängige Entsprechungen bereitstellt, sodass MCP-Entwickler dieselben Annotationen ohne Spring oder eine andere Implementierungsabhängigkeit verwenden können.