feat: Add span name conventions for MCP server spans

[gggritso]

We've been sorely missing a convention for how to make MCP server span names! This documents them, since I just ran into an issue. OTel has some newer guidelines here (e.g., they use gen_ai.tool.name) but I'm sticking to our current conventions, with the template lifted out of Python SDK.

Downstream, this would have affected how name is inferred for MCP server spans, but at this point we just use the transaction name, so it doesn't matter.

[linear-code]

CON-92

[github-actions]

Semver Impact of This PR

🟡 Minor (new features)

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New Features ✨

Attributes

• Add calculated performance scores by loewenheim in #355
• Add rpc.response.status_code attribute by alexander-alderman-webb in #352
• Add rpc.method attribute by alexander-alderman-webb in #351
• Add app vitals start attributes by buenaflor in #353
• Add process.runtime.engine.* attributes by chargome in #347

Other

• Add span name conventions for MCP server spans by gggritso in #377

Bug Fixes 🐛

Attributes

• Increase some PII values by loewenheim in #373
• Change several deprecation statuses to normalize to align with ingestion paths by constantinius in #350

Other

• (create) Replace angle brackets in file names by loewenheim in #356

Internal Changes 🔧

• (gh) Remove myself from CODEOWNERS by lcian in #354
• Bump vulnerable js packages by chargome in #359

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[betegon]

thanks @gggritso! we'll catch up with OTEL and update things, but for now, let's stick to our convention as it's how the mcp sdk from anthropic works right now.