feat: Add native MCP Instrumentation support

[liustve]

Description of changes:

Adds native OTel instrumentation for mcp following OTel's Gen's MCP semantic conventions 1.39

Instruments and wraps MCP client and server transports to capture spans for tool calls, prompts, resources, and session lifecycle.

Add auto-wiring using OTel's entry points system, so applications using ADOT Python auto-instrumentation will automatically trace mcp workflows without any code changes.

Testing

Unit tests added
Contract tests added
Manual E2E test with a FastMCP sample app, example spans shown below:

{
    "resource": {
        "attributes": {
            "aws.local.service": "test-agent",
            "aws.service.type": "gen_ai_agent",
            "telemetry.sdk.language": "python",
            "service.name": "test-agent",
            "telemetry.sdk.version": "1.39.1",
            "telemetry.auto.version": "0.14.2.dev0-aws",
            "telemetry.sdk.name": "opentelemetry"
        }
    },
    "scope": {
        "name": "amazon.opentelemetry.distro.instrumentation.mcp",
        "version": "0.14.2.dev0"
    },
    "traceId": "698d966cb0e4ac2c4add6a8dd4287515",
    "spanId": "cdc5be689ece0a0c",
    "parentSpanId": "ff36ddd067423294",
    "flags": 256,
    "name": "tools/call add",
    "kind": "CLIENT",
    "startTimeUnixNano": 1770886764840135000,
    "endTimeUnixNano": 1770886764847511000,
    "durationNano": 7376000,
    "attributes": {
        "aws.local.service": "test-agent",
        "telemetry.extended": "true",
        "aws.remote.service": "localhost:8000",
        "network.transport": "tcp",
        "aws.local.environment": "generic:default",
        "aws.remote.operation": "UnknownRemoteOperation",
        "server.address": "localhost",
        "mcp.session.id": "3c16664f7b0d484d81bf9ad78295213a",
        "aws.local.operation": "UnmappedOperation",
        "aws.span.kind": "CLIENT",
        "gen_ai.operation.name": "execute_tool",
        "gen_ai.tool.name": "add",
        "mcp.protocol.version": "2025-11-25",
        "server.port": 8000,
        "PlatformType": "Generic",
        "gen_ai.tool.call.arguments": "{\"a\": 5, \"b\": 3}",
        "mcp.method.name": "tools/call",
        "jsonrpc.request.id": "3",
        "gen_ai.tool.call.result": "meta=None content=[TextContent(type='text', text='Result: 8', annotations=None, meta=None)] structuredContent={'result': 'Result: 8'} isError=False"
    },
    "status": {
        "code": "OK"
    }
}

{
    "resource": {
        "attributes": {
            "aws.local.service": "test-mcp",
            "aws.service.type": "gen_ai_agent",
            "telemetry.sdk.language": "python",
            "service.name": "test-mcp",
            "telemetry.sdk.version": "1.39.1",
            "telemetry.auto.version": "0.14.2.dev0-aws",
            "telemetry.sdk.name": "opentelemetry"
        }
    },
    "scope": {
        "name": "amazon.opentelemetry.distro.instrumentation.mcp",
        "version": "0.14.2.dev0"
    },
    "traceId": "698d966cb0e4ac2c4add6a8dd4287515",
    "spanId": "7c0713d9a2d04672",
    "parentSpanId": "cdc5be689ece0a0c",
    "flags": 768,
    "name": "tools/call add",
    "kind": "SERVER",
    "startTimeUnixNano": 1770886764844750000,
    "endTimeUnixNano": 1770886764846329000,
    "durationNano": 1579000,
    "attributes": {
        "aws.local.service": "test-mcp",
        "telemetry.extended": "true",
        "network.transport": "tcp",
        "aws.local.environment": "generic:default",
        "mcp.session.id": "3c16664f7b0d484d81bf9ad78295213a",
        "client.address": "127.0.0.1",
        "aws.local.operation": "tools/call add",
        "aws.span.kind": "SERVER",
        "client.port": 50052,
        "gen_ai.operation.name": "execute_tool",
        "gen_ai.tool.name": "add",
        "mcp.protocol.version": "2025-11-25",
        "PlatformType": "Generic",
        "gen_ai.tool.call.arguments": "{\"a\": 5, \"b\": 3}",
        "mcp.method.name": "tools/call",
        "jsonrpc.request.id": "3"
    },
    "status": {
        "code": "OK"
    }
}

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[liustve]

Code is a bit complicated. Did review together with @wangzlei offline