⚗️ 🐛 validate feature-operation name against schema character set

[Valpertui]

Motivation

The authoritative _vital-common-schema.json restricts vital.name to the character set [\w.@$-]* (letters, digits, _, ., @, $, -) and the backend enforces this as a server-side regex on the facet path. The Browser SDK previously had no input validation on feature-operation vitals — blank names, whitespace-only names, and names with disallowed characters were all silently accepted and shipped to intake.

This PR brings the Browser SDK in line with the cross-SDK contract shared with iOS, Android, Roku, C++, and Electron

Changes

Adds validation in addOperationStepVital (inside the existing FEATURE_OPERATION_VITAL feature-flag gate):

• Blank / whitespace-only name → display.warn ("Feature operation name cannot be empty or blank. Event will not be sent."), event dropped.
• Name with characters outside [\w.@$-]* → display.warn quoting the exact backend pattern, event still emitted. The backend is the source of truth on the policy, so a client-side drop would force customers to bump the SDK if the rule is ever relaxed.
• Valid name → silent emit.
• operation_key is not subject to this rule (no schema restriction).

JS \w is always ASCII so no special handling is needed — the non-ASCII test case 'ログイン' pins that ASCII-only semantics are retained.

Test instructions

yarn test:unit --spec packages/rum-core/src/domain/vital/vitalCollection.spec.ts

The new tests exercise blank-drop, disallowed-character warn+emit (including Unicode and emoji), valid silent emit, and confirm operation_key with spaces/slashes still emits silently.

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 (CHANGELOG Unreleased entry)

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[cit-pr-commenter-54b7da]

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum	179.16 KiB	179.55 KiB	+399 B	+0.22%	✅
Rum Profiler	6.16 KiB	6.16 KiB	0 B	0.00%	✅
Rum Recorder	27.03 KiB	27.03 KiB	0 B	0.00%	✅
Logs	56.65 KiB	56.65 KiB	0 B	0.00%	✅
Rum Slim	135.00 KiB	135.39 KiB	+391 B	+0.28%	✅
Worker	23.63 KiB	23.63 KiB	0 B	0.00%	✅

🚀 CPU Performance

Pending...

🧠 Memory Performance

Action Name	Base Memory Consumption	Local Memory Consumption	𝚫
RUM - add global context	32.43 KiB	32.06 KiB	-377 B
RUM - add action	105.60 KiB	88.03 KiB	-17.57 KiB
RUM - add timing	31.89 KiB	32.66 KiB	+792 B
RUM - add error	99.80 KiB	93.67 KiB	-6.12 KiB
RUM - start/stop session replay recording	31.26 KiB	31.56 KiB	+304 B
RUM - start view	507.19 KiB	496.47 KiB	-10.72 KiB
Logs - log message	100.24 KiB	104.59 KiB	+4.35 KiB

🔗 RealWorld

[datadog-official]

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

🎯 Code Coverage (details)
• Patch Coverage: 66.67%
• Overall Coverage: 77.01% (-0.01%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 05ae58d | Docs | Datadog PR Page | Give us feedback!}

[Valpertui]

I have read the CLA Document and I hereby sign the CLA

[Valpertui]

recheck

[bcaudan]

💬 suggestion: ‏Similar to what has been done on electron, we should probably display an error if we won't send the event.