chore(correlations): TODO(v1.5) on the degraded sentinel

`degraded` is forward-looking — no path sets it true today. Pin the
intent with a TODO comment that points at the v1.5 load-shedding
branch so a future reader understands why both code paths emit
`false`. Field stays in place so downstream consumers can already
key on the shape without the load-shedding signal being live.

src/lib/analytics/correlations-fast-path.ts

@@ -95,6 +95,13 @@ export interface CorrelationHypothesesResult {
    * Today this is always `false`: the 28-day window is the canonical
    * surface. Reserved for a future "best-effort under load shedding"
    * branch.
+   *
+   * TODO(v1.5): wire this through when the load-shedding branch
+   * lands (pool-pressure detector + shorter window fallback). Until
+   * then the field is pinned to `false` by both branches and the
+   * `meta.correlations.degraded` annotate carries the same value;
+   * downstream consumers can already key on the field shape without
+   * the load-shedding signal being live.
    */
   degraded: boolean;
   /** Window the runner actually scanned, in days. */