doc: rephrase Limitations note now that manifest date_range matches parquet exactly

README.md

@@ -248,7 +248,7 @@ No personally identifiable information is present in any trace; demand and gener
 - **Intended use.** Reinforcement-learning research, load / generation forecasting, market-clearing simulation, OPF benchmarking, distribution-system control, data-centre power-shaping research, demand-response studies.
 - **Out-of-scope.** Short-term operational decisions for real grids, retail tariff design, settlement of real markets. The forecasts and prices included are historical educational artefacts, not signals for live trading.
 - **Known limitations.**
-  - Several calendar-mode traces extend slightly past the `date_range` declared in their manifest (e.g. AEMO 5-min runs through 2026-02-12; GB demand/generation through April 2026). The manifest `date_range` is a planning bound, not a strict assertion of file extent — consult the parquet itself for the authoritative range.
+  - Each manifest's `date_range` is the inclusive UTC date span of the matching parquet file at release time. Upstream sources (especially AEMO and GB BMRS) continue to publish new intervals; redownloading from the source URL will yield more data than this snapshot.
   - The Ausgrid trace is imputed; the imputation procedure is not documented in this repository.
   - The data-centre traces are stored at 5-minute (300 s) resolution. The upstream releases provide additional fields and finer resolutions; this repository ships only the columns mapped by each manifest.
   - The grid-case files use parameters consistent with the cited source systems but are not guaranteed to be byte-identical to any specific MATPOWER / IEEE PES / PEGASE release; they should not be used for compliance studies of real networks.