[jaegermcp] Log tool name in MCP middleware for tools/call requests

[lopster568]

Which problem is this PR solving?

The logging middleware logs the MCP method (e.g. tools/call) but not which specific tool was invoked. Operators cannot distinguish between search_traces, get_services, or health calls in logs, making it difficult to debug issues or understand tool-level usage patterns.

Before:

MCP request  session_id=abc  method=tools/call
MCP response session_id=abc  method=tools/call  duration=5ms

After:

MCP request  session_id=abc  method=tools/call  tool=search_traces
MCP response session_id=abc  method=tools/call  tool=search_traces  duration=5ms

This aligns with ADR-002 Phase 4 Item 10 (structured logging for debugging).

Description of the changes

• Extract tool name from CallToolParamsRaw when the method is tools/call
• Include tool field in both request and response log entries
• Add extractToolName helper that returns empty string for non-tool methods
• Refactor log field construction to build fields once and reuse for request/response
• Add TestLoggingMiddlewareToolName test that verifies tool name appears in logs
• Refactor test helpers (sendMCPRequest, deleteMCPSession) to reduce duplication

How was this change tested?

go test ./cmd/jaeger/internal/extension/jaegermcp/ -run TestLogging -v -count=1
make fmt && make lint && make test

Checklist

• I have read https://github.com/jaegertracing/jaeger/blob/main/CONTRIBUTING.md
• I have signed all commits
• I have added unit tests for the new functionality
• I ran make lint and make test successfully

[Copilot]

Pull request overview

This PR enhances Jaeger MCP’s logging middleware to include the invoked tool name for tools/call requests, improving operator visibility into tool-level usage and debugging signals.

Changes:

• Extract tool name from tools/call request params and add it as a structured tool log field on both request/response logs.
• Refactor logging middleware to build a shared set of log fields reused between request and response log entries.
• Add unit test coverage validating that tool name is present in logs for tools/call requests, and refactor test helpers to reduce duplication.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
cmd/jaeger/internal/extension/jaegermcp/logging_middleware.go	Adds tool field logging for tools/call via extractToolName and reuses built fields for request/response logs.
cmd/jaeger/internal/extension/jaegermcp/logging_middleware_test.go	Adds TestLoggingMiddlewareToolName and introduces request/session helper functions used by logging tests.

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