test(statistics): cover the store opt-out, retention and round-trip

[efirvida]

Chain Context

Field	Value
Chain	per-session statistics module (upstream Gentleman-Programming#1583)
Tracker	upstream/statistics-tracker → upstream integration PR Gentleman-Programming#1627 (draft)
Position	13 of 27
Base	upstream/statistics-12-statistics-store
Depends on	#40
Follow-up	upstream/statistics-13-store-tests (slice 14)
Review budget	172 / 400
Starts at	upstream/statistics-12-statistics-store
Ends with	test(statistics): cover the store opt-out, retention and round-trip

Chain Overview

upstream/main
 └── upstream/statistics-tracker (root, integration PR #1627)
      └── … slices 1..12 … (##40 is the immediate parent)
           └── 📍 upstream/statistics-13-store-tests
                └── … slices 14..27 …

Scope

• Includes: test(statistics): cover the store opt-out, retention and round-trip
• Excludes: every other slice. A polluted diff against upstream/statistics-12-statistics-store is a branching bug, not a scope surprise.

Verification

Focused and affected suites are green on this slice; tests and docs for this unit ship with it.