📝 Add critical patterns documentation to AGENTS.md

[thomas-lebeau]

Motivation

Improve the AGENTS.md documentation with critical patterns learned from working with the codebase, so that AI agents (and developers) avoid common pitfalls.

Changes

Adds four new subsections to the Critical Patterns section of AGENTS.md:

• Naming Conventions -- camelCase for internal code, snake_case/pascal_case only at serialization boundaries
• TypeScript Patterns -- prefer type narrowing and discriminated unions over runtime assertions
• Telemetry Usage -- clarify that addTelemetryUsage tracks static call-site info, not runtime state
• Auto-Generated Files -- never manually edit files with DO NOT MODIFY IT BY HAND headers; change the upstream schema repo instead

Test instructions

Documentation-only change. Review the added sections in AGENTS.md for accuracy and completeness.

Checklist

• Tested locally
• Tested on staging
• Added unit tests for this change.
• Added e2e/integration tests for this change.
• Updated documentation and/or relevant AGENTS.md file

[cit-pr-commenter-54b7da]

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum	169.44 KiB	169.44 KiB	0 B	0.00%	✅
Rum Profiler	4.29 KiB	4.29 KiB	0 B	0.00%	✅
Rum Recorder	24.61 KiB	24.61 KiB	0 B	0.00%	✅
Logs	56.72 KiB	56.72 KiB	0 B	0.00%	✅
Flagging	944 B	944 B	0 B	0.00%	✅
Rum Slim	126.29 KiB	126.29 KiB	0 B	0.00%	✅
Worker	23.63 KiB	23.63 KiB	0 B	0.00%	✅

🚀 CPU Performance

Pending...

🧠 Memory Performance

Pending...

🔗 RealWorld

[datadog-official]

✅ Tests

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 77.28% (+0.00%)

_{This comment will be updated automatically if new data arrives.
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