Stabilize scheduler-sensitive Swift 6.3 tests

[maxches99]

Summary

• What changed: Stabilized scheduler-sensitive Swift 6.3 tests by waiting for an observable in-flight coalescer entry and recording shared telemetry synchronously through an NSLock-protected recorder.
• Why: Post-merge release gates exposed nondeterministic timeout setup and unstructured telemetry recording that could reorder events under CI load.

DFR

• DFR link: docs/dfr/NOVA_NETWORK_V2_DFR.md
• Requirement IDs implemented: NFR-4

Traceability

Requirement ID	Code/tests reference
NFR-4	RequestCoalescerTests.inFlightTimeoutEvictsHungEntries, TelemetryRecorder, telemetry/offline queue/preset suites
Test matrix link/path	docs/dfr/NOVA_NETWORK_V2_DFR.md, docs/TRACEABILITY_PACK_v2.0.md

Test Mapping

Test ID	Type (unit/integration/ui)	Covers requirement IDs	Result
T-GATE-4	unit/integration	NFR-4	100/100 timeout; 50/50 policy telemetry; full suite 3/3
E2E-GATE	e2e	NFR-5, NFR-7 regression	31/31

Analytics Verification

• New/updated analytics requirements are implemented (AR-*)
• Event triggers validated
• Payload schema/properties validated
• Negative path verified (no false success events)
• Evidence: Existing analytics contract tests remain green; recorder now preserves synchronous hook order.

QA Sign-off

• QA owner: CI + maintainer
• Sign-off date: 2026-07-14
• Evidence links (logs/reports/screenshots): PR checks and docs/TRACEABILITY_PACK_v2.0.md

Coverage

• Unit test coverage (%): 92.45%
• Coverage is above 90%
• E2E suite executed with RUN_E2E_TESTS=1 swift test --filter E2ECoverageTests
• E2E tests use real public APIs only (no mocks/stubs/fake transports)

Release Notes ("What's New")

• Added or updated
• File/path: docs/WHATS_NEW_v2.0.md (no user-facing scope change required)
• User-facing impact summary: No runtime API change; improves release validation reliability.

Rollout

• Feature flag: N/A, test-only change
• Initial rollout percentage: 100% in CI
• Target segments: Swift 6.2 and Swift 6.3 CI jobs
• Monitoring/alerts: Two consecutive green post-merge workflows required before RC tag
• Rollback plan: Revert this isolated test-infrastructure commit if it causes regression

Checklist

• Product compliance checked against DFR
• Engineering quality reviewed (architecture/readability/testability/performance)
• No undocumented behavior changes