INST-11 · Cohort-segmented timing reporting convention

> Item derived from the fact-checking cycle analysis (**2026-07-03, v2**). New item (companion proposal **OPS-5**).

### Finding (evidence)
Cross-check "21.2 h historical" vs "~70 h current" blends the fast 2024 cohort. This is a **different** confounder from INST-1 (#2491): there the confounder is *namespace* (test/workshop); here it is *time*.

### Action
Every cadence report/dashboard segments by year/cohort and uses the **current state (2025–26)** as reference — never the historical blend.

### Impact
Current-state numbers stop being diluted by the fast 2024 cohort. Complements INST-1 (namespace confounder); both are needed.

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- **Priority:** 🟢 Low · **Effort:** P
- **Epic:** #2489

No files or tests are named. Start by locating the cadence reports and dashboards covered by this convention, then identify where cohort or year data is selected and displayed. Done means each report and dashboard segments results by year/cohort and uses the 2025–26 current state as its reference instead of a historical blend.

Vom Indexierungsmodell aus dem Issue-Text verfasst.