feat: add OTLP metrics proto definitions and reorganize directory

[mabdinur]

What does this PR do?

Adds OTLP metrics protocol buffer definitions and reorganizes OTLP code into a dedicated directory.

Motivation

Prepares infrastructure for OTLP metrics support by adding proto definitions and improving code organization.

Changes

• Add otlp/metrics.proto (OTLP v1.7,0 metrics specification)
• Add otlp/metrics_service.proto (OTLP v1.7,0 metrics service definition)
• Update protobuf_loader.js to load both logs and metrics proto types
• Rename protos/ → otlp/ directory for better organization
• Update all import paths across the codebase

Testing

• All existing tests pass (no functionality changes)
• All protobuf files can be parsed by opentelemetry logs tests
• No linter errors

Checklist

• Unit tests.
• Integration tests.
• Benchmarks.
• TypeScript definitions.
• TypeScript tests.
• API documentation.
• CI jobs/workflows.

Additional Notes

[github-actions]

Overall package size

Self size: 12.78 MB
Deduped: 113.51 MB
No deduping: 128.53 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------| | @datadog/libdatadog | 0.7.0 | 35.02 MB | 35.02 MB | | @datadog/native-appsec | 10.2.1 | 20.64 MB | 20.65 MB | | @datadog/native-iast-taint-tracking | 4.0.0 | 11.72 MB | 11.73 MB | | @datadog/pprof | 5.10.0 | 9.91 MB | 10.3 MB | | @opentelemetry/resources | 1.9.1 | 306.54 kB | 7.46 MB | | @opentelemetry/core | 1.30.1 | 908.66 kB | 7.16 MB | | protobufjs | 7.5.4 | 2.95 MB | 5.73 MB | | @datadog/wasm-js-rewriter | 4.0.1 | 2.85 MB | 3.58 MB | | @datadog/native-metrics | 3.1.1 | 1.02 MB | 1.43 MB | | @opentelemetry/api-logs | 0.205.0 | 201.51 kB | 1.42 MB | | @opentelemetry/api | 1.9.0 | 1.22 MB | 1.22 MB | | jsonpath-plus | 10.3.0 | 617.18 kB | 1.08 MB | | import-in-the-middle | 1.14.4 | 123.18 kB | 851.76 kB | | lru-cache | 10.4.3 | 804.3 kB | 804.3 kB | | opentracing | 0.14.7 | 194.81 kB | 194.81 kB | | source-map | 0.7.6 | 185.63 kB | 185.63 kB | | pprof-format | 2.2.1 | 163.06 kB | 163.06 kB | | @datadog/sketches-js | 2.1.1 | 109.9 kB | 109.9 kB | | lodash.sortby | 4.7.0 | 75.76 kB | 75.76 kB | | ignore | 7.0.5 | 63.38 kB | 63.38 kB | | istanbul-lib-coverage | 3.2.2 | 34.37 kB | 34.37 kB | | rfdc | 1.4.1 | 27.15 kB | 27.15 kB | | dc-polyfill | 0.1.10 | 26.73 kB | 26.73 kB | | @isaacs/ttlcache | 1.4.1 | 25.2 kB | 25.2 kB | | tlhunter-sorted-set | 0.1.0 | 24.94 kB | 24.94 kB | | shell-quote | 1.8.3 | 23.74 kB | 23.74 kB | | limiter | 1.1.5 | 23.17 kB | 23.17 kB | | retry | 0.13.1 | 18.85 kB | 18.85 kB | | semifies | 1.0.0 | 15.84 kB | 15.84 kB | | jest-docblock | 29.7.0 | 8.99 kB | 12.76 kB | | crypto-randomuuid | 1.0.0 | 11.18 kB | 11.18 kB | | ttl-set | 1.0.0 | 4.61 kB | 9.69 kB | | mutexify | 1.4.0 | 5.71 kB | 8.74 kB | | path-to-regexp | 0.1.12 | 6.6 kB | 6.6 kB | | module-details-from-path | 1.0.4 | 3.96 kB | 3.96 kB |

_{🤖 This report was automatically generated by heaviest-objects-in-the-universe}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.05%. Comparing base (2555791) to head (52a81ee).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6657      +/-   ##
==========================================
+ Coverage   84.00%   84.05%   +0.05%     
==========================================
  Files         497      497              
  Lines       20940    21007      +67     
==========================================
+ Hits        17591    17658      +67     
  Misses       3349     3349              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-10-14 20:35:42

Comparing candidate commit 52a81ee in PR branch munir/otlp-infrastructure with baseline commit 2555791 in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 1605 metrics, 65 unstable metrics.

[mabdinur]

Follow up PR: #6659