feat: telemetry contract v2 #375

Why

Telemetry scope must match the dashboard filter (design: Usage, Observability and telemetry).

In scope

selection.scope all|managed; the X7 decision; identity in the cache; docs say the export is not OTLP (O06).

Out of scope

OTel (v5).

Acceptance criteria

• Exports never carry paths
• The contract test pins v2

Dependencies

Blocked by: #369, #374

Blocks: #377, #382, #388, #404

Plan

• Release: 4.0.0-beta.4
• Size: size:M · Workstream: ws:project-scope
• Epic: feat: project-scope P6, the dashboard for all work (epic) #301
• Card: P6-13 in the card inventory
• Sources: Design (docs(plans): project-scoped management design and its prerequisites #289) Usage, Observability and telemetry; v5 impact review (docs(plans): v4 GA master plan, supersession ledger and v5 registers #290) O06, X7

Verification

• node scripts/run-tests.mjs focus (new telemetry tests)