chore(routes): remove orphan /api/medications/intake-summary endpoint

The GET handler had no fetch caller and the queryKeys.medicationIntakeSummary
entry was never consumed in any useQuery. Strip the route file, the
factory entry, the medicationDependentKeys reference, and an outdated
quick-add doc comment.

src/components/dashboard/medication-intake-quick-add.tsx

@@ -58,7 +58,7 @@ import {
  *      shaped the same as `MoodForm`).
  *
  * On success: invalidate `medicationDependentKeys` (medications +
- * analytics + insights + intake-summary + achievements) PLUS the
+ * analytics + insights + achievements) PLUS the
  * inline per-medication compliance chart key so the detail page tile
  * refreshes if it happens to be mounted elsewhere in the app.
  *