test(statistics): cover the transport encoder and publisher

[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	15 of 27
Base	upstream/statistics-14-statistics-rpc
Depends on	#42
Follow-up	upstream/statistics-15-rpc-tests (slice 16)
Review budget	156 / 400
Starts at	upstream/statistics-14-statistics-rpc
Ends with	test(statistics): cover the transport encoder and publisher

Chain Overview

upstream/main
 └── upstream/statistics-tracker (root, integration PR #1627)
      └── … slices 1..14 … (##42 is the immediate parent)
           └── 📍 upstream/statistics-15-rpc-tests
                └── … slices 16..27 …

Scope

• Includes: test(statistics): cover the transport encoder and publisher
• Excludes: every other slice. A polluted diff against upstream/statistics-14-statistics-rpc 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.