fix: improve MCP server plugin path handling and backward compatibility for argsPosition

[Aias00]

improve MCP server plugin path handling and backward compatibility for argsPosition

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[Copilot]

Pull request overview

This PR improves MCP server path normalization/registration in the gateway plugin, adds backward compatibility for nested argsPosition configs (while making root-level argsPosition canonical), and tightens session cleanup to avoid leaking exchange references.

Changes:

• Add backward-compatible parsing for nested requestTemplate.argsPosition, and update the MCP client generator to emit both root-level and nested argsPosition.
• Rework MCP server path handling (normalization, route registration, supported-protocol lookup) and update tests to match the new path semantics.
• Ensure ShenyuMcpExchangeHolder entries are removed when SSE/Streamable HTTP sessions are closed/shutdown.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
shenyu-plugin/shenyu-plugin-mcp-server/src/main/java/org/apache/shenyu/plugin/mcp/server/request/RequestConfigHelper.java	Adds fallback parsing for nested argsPosition.
shenyu-client/shenyu-client-mcp/shenyu-client-mcp-common/src/main/java/org/apache/shenyu/client/mcp/generator/McpRequestConfigGenerator.java	Generates canonical root-level argsPosition and keeps nested form for compatibility.
shenyu-plugin/shenyu-plugin-mcp-server/src/main/java/org/apache/shenyu/plugin/mcp/server/manager/ShenyuMcpServerManager.java	Updates normalization + route registration logic; adds helpers for joining/normalizing paths.
shenyu-plugin/shenyu-plugin-mcp-server/src/main/java/org/apache/shenyu/plugin/mcp/server/handler/McpServerPluginDataHandler.java	Normalizes selector paths and uses normalized paths when creating/removing servers/transports.
shenyu-plugin/shenyu-plugin-mcp-server/src/main/java/org/apache/shenyu/plugin/mcp/server/transport/ShenyuSseServerTransportProvider.java	Cleans ShenyuMcpExchangeHolder on cancel/dispose and during graceful shutdown.
shenyu-plugin/shenyu-plugin-mcp-server/src/main/java/org/apache/shenyu/plugin/mcp/server/transport/ShenyuStreamableHttpServerTransportProvider.java	Cleans ShenyuMcpExchangeHolder when removing sessions.
shenyu-client/shenyu-client-mcp/shenyu-client-mcp-register/src/main/java/org/apache/shenyu/client/mcp/McpServiceEventListener.java	Avoids AIOOBE when no servers[]; uses merged URL for metadata path.
shenyu-plugin/shenyu-plugin-mcp-server/src/test/java/org/apache/shenyu/plugin/mcp/server/request/RequestConfigHelperTest.java	Adds coverage for nested argsPosition compatibility.
shenyu-plugin/shenyu-plugin-mcp-server/src/test/java/org/apache/shenyu/plugin/mcp/server/manager/ShenyuMcpServerManagerTest.java	Updates expectations to match new path normalization behavior.
shenyu-plugin/shenyu-plugin-mcp-server/src/test/java/org/apache/shenyu/plugin/mcp/server/handler/McpServerPluginDataHandlerTest.java	Updates expected transport/server paths (no /** passed to manager).
shenyu-plugin/shenyu-plugin-mcp-server/src/test/java/org/apache/shenyu/plugin/mcp/server/McpServerPluginIntegrationTest.java	Updates integration assertions to use the normalized server path.

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[Copilot]

handlerRule now guards against ruleData == null, but it can still call addTool(server.getPath(), ...) later with a null/blank server.getPath() (e.g., selector had no URI condition or cached server path is empty). That can throw inside ShenyuMcpServerManager (ConcurrentHashMap null key). Consider also gating tool registration on server != null && StringUtils.isNotBlank(server.getPath()) (consistent with the removeRule check).