fix: keep entry form mounted when a new entry is first saved

On mobile, typing the first characters of a work description on a new
entry caused the form to remount: the auto-save POST replaced the temp
entry with the server copy, changing its React key, which destroyed the
textarea, dropped focus and closed the keyboard.

- Key EntryForm on a stable clientKey that survives the id swap
- Merge only the server id into the local entry so keystrokes typed
  while the create request is in flight are kept
- Track temp-id -> real-id and in-flight creates so queued changes
  become PUTs instead of duplicate POSTs; deletes resolve to the real row

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

frontend/src/components/DayCard.jsx

@@ -65,7 +65,7 @@ export default function DayCard({ date, entries, homeowners, onEntryChange, onAd
         <div className="px-4 pb-4 space-y-3">
           {(entries || []).map((entry) => (
             <EntryForm
-              key={entry.id}
+              key={entry.clientKey || entry.id}
               entry={entry}
               homeowners={homeowners}
               onHomeownerAdded={onHomeownerAdded}

frontend/src/pages/Timesheet.jsx

@@ -58,6 +58,16 @@ export default function Timesheet() {
   const [overtime, setOvertime] = useState(null);
   const saveTimer = useRef(null);
   const pendingChanges = useRef({});
+  // Client-created entries keep a temp id until the server assigns a real one.
+  // idMap:    tempId -> realId (after create resolves)
+  // creating: tempId -> Promise<realId> (while create is in flight)
+  const idMap = useRef({});
+  const creating = useRef({});
+
+  function makeNewEntry(date) {
+    const id = `new-${date}-${Date.now()}-${Math.random().toString(36).slice(2, 7)}`;
+    return { id, clientKey: id, date, homeownerId: '', hoursWorked: '', workDescription: '', _isNew: true };
+  }
 
   const weekDates = getWeekDates(selectedDate);
   const weekParam = formatWeekParam(selectedDate);
@@ -85,10 +95,12 @@ export default function Timesheet() {
       // Ensure at least one empty entry per day
       weekDates.forEach((d) => {
         if (byDate[d].length === 0) {
-          byDate[d] = [{ id: `new-${d}-0`, date: d, homeownerId: '', hoursWorked: '', workDescription: '', _isNew: true }];
+          byDate[d] = [makeNewEntry(d)];
         }
       });
 
+      idMap.current = {};
+      creating.current = {};
       setEntries(byDate);
       setTimesheet(timesheetRes.data?.timesheet || timesheetRes.data);
       setHomeowners(homeownersRes.data.homeowners || homeownersRes.data || []);
@@ -124,18 +136,51 @@ export default function Timesheet() {
     };
 
     try {
-      if (data._isNew || entryId.startsWith('new-')) {
-        const res = await api.post('/entries', payload);
-        // Replace temp ID with real ID
-        setEntries((prev) => {
-          const dk = data.date;
-          return {
-            ...prev,
-            [dk]: prev[dk].map((e) => (e.id === entryId ? { ...res.data.entry || res.data, date: dk } : e)),
-          };
+      const isTemp = entryId.startsWith('new-');
+      let realId = isTemp ? idMap.current[entryId] : entryId;
+
+      // A create for this temp id is already in flight — wait for it, then update.
+      if (isTemp && !realId && creating.current[entryId]) {
+        realId = await creating.current[entryId];
+      }
+
+      if (isTemp && !realId) {
+        const createPromise = api.post('/entries', payload).then((res) => {
+          const created = res.data.entry || res.data;
+          idMap.current[entryId] = created.id;
+          // Merge the server id into the existing local entry. Keep the
+          // clientKey (so React does not remount the form) and keep whatever
+          // the user has typed since the request was sent.
+          setEntries((prev) => {
+            const dk = data.date;
+            return {
+              ...prev,
+              [dk]: (prev[dk] || []).map((e) =>
+                e.id === entryId
+                  ? {
+                      ...e,
+                      id: created.id,
+                      clientKey: e.clientKey,
+                      date: dk,
+                      homeownerId: e.homeownerId,
+                      hoursWorked: e.hoursWorked,
+                      workDescription: e.workDescription,
+                      _isNew: false,
+                    }
+                  : e
+              ),
+            };
+          });
+          return created.id;
         });
+        creating.current[entryId] = createPromise;
+        try {
+          await createPromise;
+        } finally {
+          delete creating.current[entryId];
+        }
       } else {
-        await api.put(`/entries/${entryId}`, payload);
+        await api.put(`/entries/${realId}`, payload);
       }
       setSaveStatus('saved');
     } catch (err) {
@@ -164,27 +209,27 @@ export default function Timesheet() {
   }
 
   function handleAddEntry(date) {
-    const newEntry = {
-      id: `new-${date}-${Date.now()}`,
-      date,
-      homeownerId: '',
-      hoursWorked: '',
-      workDescription: '',
-      _isNew: true,
-    };
+    const newEntry = makeNewEntry(date);
     setEntries((prev) => ({ ...prev, [date]: [...(prev[date] || []), newEntry] }));
   }
 
   async function handleDeleteEntry(entryId) {
     try {
-      if (!entryId.startsWith('new-')) {
-        await api.delete(`/entries/${entryId}`);
+      // Resolve a temp id to its server id if the create already happened
+      // (or is still in flight) so we do not orphan a row on the server.
+      let realId = entryId;
+      if (entryId.startsWith('new-')) {
+        realId = idMap.current[entryId] || (creating.current[entryId] ? await creating.current[entryId] : null);
       }
+      if (realId) {
+        await api.delete(`/entries/${realId}`);
+      }
+      delete pendingChanges.current[entryId];
       setEntries((prev) => {
         const updated = {};
         Object.entries(prev).forEach(([dk, dayEntries]) => {
-          const filtered = dayEntries.filter((e) => e.id !== entryId);
-          updated[dk] = filtered.length > 0 ? filtered : [{ id: `new-${dk}-0`, date: dk, homeownerId: '', hoursWorked: '', workDescription: '', _isNew: true }];
+          const filtered = dayEntries.filter((e) => e.id !== entryId && e.id !== realId);
+          updated[dk] = filtered.length > 0 ? filtered : [makeNewEntry(dk)];
         });
         return updated;
       });