No test asserts that the Sentinel tools reach the MCP server catalog

Problem/Motivation

mcp_sentinel_server has no test that goes through MCP Server itself. McpServerRegistrationTest checks that the Sentinel tools are discoverable by plugin.manager.tool (Tool API), that they instantiate, and that each derives a valid scope. It never asks MCP Server's tool plugin manager or McpServerFactory what would be listed by tools/list.

MCP Server 2.0.0-beta3 moved tool plugin discovery from src/Plugin/Tool to src/Plugin/mcp_server/Tool (mcp_server #3585914). With a Tool Bridge commit from before its matching move (mcp_server_tool_bridge #3618722), the bridge's ToolApi plugin is not discovered, and every Sentinel tool disappears from /mcp. initialize and tools/list still return HTTP 200, with no tools and no error.

On that pairing McpServerRegistrationTest passes: 8 tests, 136 assertions, the same as on a working pairing. The Tool Bridge's own ToolApiRegistrationTest fails there, so the break is detectable. Sentinel's suite does not detect it.

Steps to reproduce

1. Install MCP Sentinel 2.22.0 with mcp_sentinel_server, drupal/mcp_server 2.0.0-beta4 and drupal/mcp_server_tool_bridge at 1.x commit 569be5d1.
2. Run modules/mcp_sentinel_server/tests/src/Kernel/McpServerRegistrationTest.php. It passes.
3. Request tools/list on /mcp with a token for a designated consumer holding mcp_read mcp_write mcp_config mcp_config_read. The catalog is empty. With the bridge at be13f9ff the same request lists 11 tools.

Proposed resolution

Add a Kernel test in mcp_sentinel_server that enables mcp_server and mcp_server_tool_bridge, runs the setup that creates the bridge configs, and asserts that plugin.manager.mcp_server.tool has a tool_api__<id> definition for every entry in McpSentinelServerCommands::TOOLS. If practical, also build the server with McpServerFactory under a designated-consumer request and assert the listed names, since discovery access is decided per request.

Remaining tasks

• Write the test and confirm it fails on the pairing above and passes on a matching one.
• Decide whether the test lane should pin the Tool Bridge commit or follow 1.x.

User interface changes

None.

API changes

None.

Data model changes

None.