fix(webxr): keep config changes from re-arming warm-up watchdogs during idle

[gareth-morgan-nv]

Summary

Follow-up to #1260 addressing its remaining review findings (the review landed while #1260 was being merged).

• Config change during idle: re-registering the effect on a config change re-armed the warm-up watchdog even while idle frames were arriving, so a config edit during idle (or its quiet window) disconnected before quiet period plus the phase budget, and the later quiet expiry could arm a second timer and orphan the first. The re-arm is now skipped while idle is active or after real video was seen (the idle quiet timer resumes the watchdog itself), and each arm function clears any existing timer before replacing it.
• One source of truth: removed idleFramesActiveRef; idleStatusRef.current.active is used instead.
• Test coverage: StreamAttachTimeoutTest gains idle-then-silence scenarios for warm-up that never began and warm-up that stalled (the watchdog must fire no earlier than quiet period plus phase budget after the last idle frame), and a scenario with config changes during idle and inside the quiet window.

Still inert today: the SDK does not currently emit the Received idle frame log and the session logLevel is Info.

Test plan

• StreamAttachTimeoutTest.spec.js (5 tests) passes 3/3; reverting the config guard fails the config-change scenario, and making the quiet callback never re-arm fails all three idle-silence scenarios
• jest (119 tests), eslint, prettier, SKIP=check-copyright-year pre-commit run --all-files clean; tsc --noEmit shows no errors in the touched files
• Playwright specs are not run in CI, so that run is local only

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes
  • Improved stream startup timeout handling during idle periods, preventing warm-up timers from starting or restarting at the wrong time.
  • Warm-up monitoring now resumes after idle frames stop and the quiet period has elapsed, including when configuration changes during that period.
  • Replacing a timer now clears the existing timer of the same type, helping avoid conflicting timeout behavior.

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📥 Commits

Reviewing files that changed from the base of the PR and between 655e647 and 6b5e62b.

📒 Files selected for processing: 3

• deps/cloudxr/webxr_client/helpers/react/CloudXRComponent.tsx
• deps/cloudxr/webxr_client/tests/mock/StreamAttachTimeoutTest.tsx
• deps/cloudxr/webxr_client/tests/playwright/StreamAttachTimeoutTest.spec.js

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📝 Walkthrough

The component now uses idle status as the source for idle-frame state. Timer-arm helpers clear an existing timer before scheduling a replacement. Config-change watchdog re-arming skips periods when idle frames are active or real video has been seen, and arms only the timer for the incomplete warm-up phase. Mock and Playwright tests cover three idle-silence scenarios, including config changes during idle and the quiet period.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: ⚪ Minimal · up to 6b5e6

No actionable issue remains identified; the PR is mergeable after normal checks.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 40.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 5 functions across 3 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly and concisely describes the main change: preventing configuration changes from re-arming WebXR warm-up watchdogs during idle frames.
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

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