fix: a review window needs a baseline — say which one, refuse ones that have none

- charter: a window starting before the data or longer than 12 weeks is split
  (last 6 weeks vs the 8 before); REVIEWED always names the compared periods,
  never the requested span or the whole table
- Run review: shows the data's span, previews the exact recent and baseline
  periods, blocks a window whose baseline would fall before the first claim,
  and sends 'data as of' only when no window end is given

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/screens/RunReviewScreen.tsx

@@ -1,7 +1,9 @@
 import { useState } from 'react';
 import { useNavigate } from 'react-router-dom';
 import { Brain, CalendarRange, Database, Radar } from 'lucide-react';
-import { useZino } from '../api/provider';
+import { useQuery, useZino } from '../api/provider';
+import { addDays } from '../api/charts';
+import { str } from '../format';
 import { ACT, LAKEHOUSE, QUIET_MORNING_AS_OF, WORKFLOW } from '../api/config';
 import { Button, Card, ErrorNote, Input, Label } from '../components/core';
 import { shortDate } from '../format';
@@ -28,14 +30,29 @@ export function RunReviewScreen() {
   const [from, setFrom] = useState('');
   const [to, setTo] = useState('');
 
+  // The data's own span, so a window cannot be set where there is nothing to
+  // compare: a start before the first claim leaves no baseline, and a run on
+  // such a window would have to improvise one.
+  const stats = useQuery(() => client.rows('dni-rv-lakehouse-tables', { limit: 10 }), []);
+  const claimsStats = stats.data?.find((r) => str(r.table_name) === 'claims');
+  const dataFrom = str(claimsStats?.from_date).slice(0, 10) || null;
+  const dataTo = str(claimsStats?.to_date).slice(0, 10) || null;
+
   // The window Ava will actually use, so the reviewer sees it before pressing Run.
   const effectiveTo = to || asOf;
+  const weeks = from && effectiveTo ? Math.round((new Date(effectiveTo).getTime() - new Date(from).getTime()) / 604800000) : null;
+  const split = weeks != null && weeks > 12;
+  const recentFrom = split && effectiveTo ? addDays(effectiveTo, -41) : from || (effectiveTo ? addDays(effectiveTo, -41) : '');
+  const baseFrom = recentFrom ? addDays(recentFrom, -56) : '';
+  const baseTo = recentFrom ? addDays(recentFrom, -1) : '';
   const dateErr =
     from && effectiveTo && from > effectiveTo
       ? 'The window must start before it ends.'
       : to && asOf && to > asOf
         ? '"Window to" cannot be after "data as of".'
-        : null;
+        : dataFrom && baseFrom && baseFrom < dataFrom
+          ? `The 8-week baseline before ${shortDate(recentFrom)} needs data from ${shortDate(baseFrom)}, but the data begins ${shortDate(dataFrom)}. Start the window on or after ${shortDate(addDays(dataFrom, 56))}.`
+          : null;
 
   async function run(custom: boolean) {
     setBusy(custom ? 'custom' : 'now');
@@ -45,7 +62,8 @@ export function RunReviewScreen() {
       // reviewer set, so a plain run is a genuinely empty submission.
       const data: Record<string, string> = {};
       if (custom) {
-        if (asOf) data.review_as_of__review = asOf;
+        // "Window to" is the ceiling; "data as of" only matters when no window end is given.
+        if (asOf && !to) data.review_as_of__review = asOf;
         if (from) data.review_from__review = from;
         if (to) data.review_to__review = to;
       }
@@ -121,6 +139,7 @@ export function RunReviewScreen() {
             <p className="mt-0.5 text-sm text-muted">
               Replay a past morning, or point the review at a specific period. Leave a date blank to
               use the default.
+              {dataFrom && dataTo ? ` Data available ${shortDate(dataFrom)} – ${shortDate(dataTo)}, ${dataTo.slice(0, 4)}.` : ''}
             </p>
           </div>
         </div>
@@ -150,11 +169,12 @@ export function RunReviewScreen() {
             <>
               Ava will compare{' '}
               <span className="font-semibold text-ink">
-                {from ? shortDate(from) : effectiveTo ? '6 weeks before' : 'the last 6 weeks'}
+                {recentFrom ? `${shortDate(recentFrom)} – ${shortDate(effectiveTo)}` : 'the last 6 weeks'}
-                {from || effectiveTo ? ` – ${effectiveTo ? shortDate(effectiveTo) : 'latest data'}` : ''}
               </span>{' '}
-              against the 8 weeks before it
+              against{' '}
-              {asOf ? `, treating ${shortDate(asOf)} as the latest date` : ''}.
+              <span className="font-semibold text-ink">{baseFrom ? `${shortDate(baseFrom)} – ${shortDate(baseTo)}` : 'the 8 weeks before'}</span>
+              {effectiveTo ? `, ignoring anything after ${shortDate(effectiveTo)}` : ''}.
+              {split ? ` A window longer than 12 weeks has no baseline of its own, so its last 6 weeks are compared with the 8 before them.` : ''}
             </>
           )}
         </p>