fix(P13): route transient Segment send-loop errors off Sentry

[eordano]

UNITY-EXPLORER-P13 (637 evts/242 users — widest reach): "Segment error: Error executing send loop (will retry): ClientError {...}". The Rust Segment SDK's background send loop reports transient, self-recovering upload failures via ErrorCallback, which called ReportHub.LogException → Sentry (error level). The existing once-per-session guard still emitted one Sentry error per user. Route "(will retry)" messages to LogWarning on ReportHandler.DebugLog (local log, never Sentry); genuine non-transient Segment errors keep Sentry reporting. Removed the now-unused ONCE_PATTERN_ALREADY_CAUGHT field. Report-noise reduction. Unverified.

fixes #8574

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Supersedes #9406: moved from the fork into the org repo so CI workflows receive repository secrets (fork PRs do not).

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[claude]

Claude finished @eordano's task in 1m 18s —— View job

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Review: PR #9420 — route transient Segment send-loop errors off Sentry

• Read PR diff and changed file
• Review code correctness & standards
• Security/dependency check (labels: new-dependency, ext-contribution)
• Post review

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Verdict: LGTM. The change does exactly what it says and is a clean, targeted noise reduction. No blocking issues.

Behavioral change (correct)

	Before	After
First (will retry) msg	LogException → Sentry (1 error/session/user)	LogWarning → DebugLog only, never Sentry
Subsequent (will retry)	silently dropped	LogWarning → DebugLog only
Non-transient errors	LogException → Sentry	unchanged (still Sentry)

Verified against the source:

• ReportHub.LogWarning(ReportData, object, ReportHandler) exists (ReportHub.cs:57) and ReportCategory.ANALYTICS converts to ReportData (same conversion the untouched LogException call on line 244 relies on). ✅
• ReportHandler.DebugLog = 1 and All = DebugLog | Sentry (ReportHandler.cs:16,26), so passing DebugLog genuinely bypasses the Sentry handler. ✅
• Removing the now-unused ONCE_PATTERN_ALREADY_CAUGHT static field and its typo'd comment is correct dead-code cleanup — no other references. ✅

Minor observations (non-blocking, optional)

1. Log volume trade-off. The old code suppressed all but the first (will retry) message; the new code writes a local warning for every transient failure. That's fine (DebugLog is cheap and never leaves the machine, and it's arguably better for local diagnostics), but if the Rust send loop retries tightly during an outage this will be chattier in the local log. Acceptable given the Sentry-noise goal.
2. Stale identifier names. ONCE_PATTERN / isCaught were named for the old "log once" semantics, which no longer exist — the pattern now simply classifies transient vs. genuine errors. A rename like TRANSIENT_PATTERN / isTransient would read truer, but it's cosmetic.

Security / dependency review (per new-dependency + ext-contribution labels)

Despite the labels, this diff contains no actual dependency, binary, or workflow changes — it is a single .cs edit (+6/-10) to RustSegmentAnalyticsService.cs.

• No changes to Packages/manifest.json or packages-lock.json.
• No new/modified native or managed binaries under Assets/** (pre-computed binary list: None).
• No .asmdef / build-script / editor-hook changes.
• No .github/workflows/ or .github/prompts/ changes (pre-computed: None).

No new runtime capability, network, filesystem, or reflection surface is introduced — the code strictly reduces what gets reported externally.

DEPENDENCY_REVIEW: PASS

[eordano]

Closed in favor of the compound PR #9430 (team decision — all fixes in this set land and iterate there; each fix remains individually reviewable as its own merge commit in #9430).