PROC-2 · Stalled backlog (umbrella: 2a + 2b)

> **Umbrella** · split into two child issues (see task list). Kept open as a tracking umbrella (not closed, so sub-issue progress stays visible). Item derived from the fact-checking cycle analysis (**2026-07-03, v2**).

### Finding (evidence)
The ~215 open tasks are **not one block** — they split by idle time and content into two distinct governance problems, acted on separately below.

### Split
- [ ] #2509 — PROC-2a · Purge/diagnose the **~60–75 abandoned** tasks (empty `reviewData`, ~590–660 d idle) — 🔴
- [ ] #2510 — PROC-2b · Triage/SLA the **~142–155 stuck-active** tasks (~226–235 d idle; `main`-only ~108→~70 d) — 🔴

### Notes
- Both depend on INST-4 (#2494) for the `abandoned`/`archived` state.
- The technical "how" for 2b is TECH-4 (SLA + auto-owner).

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- **Epic:** #2490

This is a tracking umbrella, not a direct implementation issue. Start by reading the child issues #2509 and #2510, plus dependency #2494 and the referenced TECH-4 item, to understand where the actual work lives. Done for this issue means the child work is completed or the umbrella checklist is updated, not a standalone patch here.

Rédigé par le modèle d'indexation à partir du texte de l'issue.