refactor(remote_config): move capability registration to feature modules

[watson]

What does this PR do?

Refactors remote config capability and handler registration to improve separation of concerns. Moves feature-specific remote config setup from a central location into their respective feature modules, following the same pattern already used by AppSec.

Key changes:

• Creates config/remote_config.js for client library config capabilities (APM_TRACING_*)
• Creates openfeature/remote_config.js for OpenFeature capabilities (FFE_FLAG_CONFIGURATION_RULES)
• Renames RemoteConfigManager → RemoteConfig and remote_config/manager.js → remote_config/index.js
• Simplifies proxy.js to instantiate RemoteConfig directly instead of through wrapper function

Motivation

Motivation

This refactoring establishes a clear pattern where each feature manages its own remote config capabilities and handlers together:

• Core features (like APM tracing) → always registered
• Optional features (like AppSec) → registered only when feature is enabled

OpenFeature is an exception to this pattern: it always registers the FFE_FLAG_CONFIGURATION_RULES capability (required by parametric tests since v5.72.0), but only registers its handler when config.experimental.flaggingProvider.enabled is true. This hybrid approach satisfies test requirements while keeping the experimental feature properly gated.

Additional Notes

Reviewing this PR:
The diff is large but mostly consists of code being moved between files. To review more easily:

1. File renames (no logic changes, just find/replace):

   • remote_config/manager.js → remote_config/index.js
   • test/remote_config/manager.spec.js → test/remote_config/index.spec.js
   • Class RemoteConfigManager → RemoteConfig (throughout)

2. New files with moved code:

   • config/remote_config.js - client library config capabilities moved from old remote_config/index.js + APM_TRACING handler moved from proxy.js
   • openfeature/remote_config.js - FFE capability + handler moved from proxy.js

3. Modified files:

   • proxy.js - Removed old wrapper, now instantiates RemoteConfig directly; handlers moved to feature modules
   • test/proxy.spec.js - Updated imports and assertions to match new structure

4. Assertion lib:

   • Replaced chai with node:assert/strict in remote_config tests for consistency

No functional changes to remote config behavior, purely structural refactoring.

[watson]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• feat(debugger): add Remote Enablement support #7137
• refactor(remote_config): move capability registration to feature modules #7127 👈 (View in Graphite)
• refactor(remote_config): move appsec-specific logic to appsec folder #7122
• refactor(remote-config): replace kPreUpdate with batch handler API (DEBUG-4402) #7121
• master

This stack of pull requests is managed by Graphite. Learn more about stacking.

[github-actions]

Overall package size

Self size: 4.36 MB
Deduped: 5.19 MB
No deduping: 5.19 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------| | import-in-the-middle | 2.0.0 | 68.46 kB | 797.03 kB | | dc-polyfill | 0.1.10 | 26.73 kB | 26.73 kB |

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

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-12-19 19:13:03

Comparing candidate commit 408e3f5 in PR branch watson/DEBUG-4402/even-more-rc-split with baseline commit 69d7527 in branch watson/DEBUG-4402/split-rc-and-appsec.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 292 metrics, 28 unstable metrics.

[codecov]

Codecov Report

❌ Patch coverage is 97.19626% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.82%. Comparing base (69d7527) to head (408e3f5).

Files with missing lines	Patch %	Lines
packages/dd-trace/src/remote_config/index.js	97.34%	5 Missing ⚠️
packages/dd-trace/src/config/remote_config.js	92.30%	1 Missing ⚠️

Additional details and impacted files

@@                            Coverage Diff                            @@
##           watson/DEBUG-4402/split-rc-and-appsec    #7127      +/-   ##
=========================================================================
- Coverage                                  84.82%   84.82%   -0.01%     
=========================================================================
  Files                                        523      524       +1     
  Lines                                      22213    22217       +4     
=========================================================================
+ Hits                                       18842    18845       +3     
- Misses                                      3371     3372       +1     

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