feat(workspace): journal with one note per day and a calendar

- journal_days (migration 8) maps a person's day to an ordinary note;
  GET /journal lists the days, POST /journal/{date} opens or creates one
- the journal sits on top of the notes sidebar: days below each other
  (today first, older ones load while scrolling), a calendar with month
  and year picker follows the day in view and jumps to any day
- the header shares the day in view; journal notes stay out of the folder
  tree; can be switched off per device under Darstellung

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/features/workspace/WorkspaceView.tsx

@@ -23,6 +23,7 @@ import {
   Clock,
   AlertTriangle,
   Loader2,
+  CalendarDays,
 } from 'lucide-react';
 import {
   Document,
@@ -36,6 +37,7 @@ import {
   TrashedDocument,
   UnifiedShare,
   User,
+  JournalDay,
 } from '../../lib/types';
 import {
   api,
@@ -49,6 +51,9 @@ import { useMobileActions } from '../../context/MobileActionContext';
 import { DocumentEditor, DocSaveStatus, DocHeaderStatus } from './DocumentEditor';
 import { PresenceAvatars } from './PresenceAvatars';
 import { TrashView } from './TrashView';
+import { JournalView } from './JournalView';
+import { JournalCalendar } from './JournalCalendar';
+import { isJournalEnabled, todayISO } from '../../lib/journal';
 import { MergeDialog } from './MergeDialog';
 import { CountBadge } from '../../components/CountBadge';
 import { extractHashtags } from '../../lib/hashtags';
@@ -63,7 +68,7 @@ interface WorkspaceViewProps {
   onOpenSearch?: () => void;
 }
 
-type WorkspaceSubView = 'editor' | 'tag_detail' | 'todos' | 'tags' | 'trash';
+type WorkspaceSubView = 'editor' | 'tag_detail' | 'todos' | 'tags' | 'trash' | 'journal';
 
 interface FolderTreeNode {
   name: string;
@@ -327,6 +332,33 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
   useEffect(() => {
     reloadTrash();
   }, [reloadTrash]);
+
+  // Journal: one note per day, listed separately from the folder tree (can be switched off per device)
+  const [journalEnabled] = useState(isJournalEnabled);
+  const [journalDays, setJournalDays] = useState<JournalDay[]>([]);
+  const [journalExtra, setJournalExtra] = useState<string[]>([]);
+  const [journalActive, setJournalActive] = useState(todayISO);
+  const [journalJump, setJournalJump] = useState<{ date: string; nonce: number } | null>(null);
+  const reloadJournal = useCallback(() => {
+    if (!journalEnabled) return;
+    api.getJournal().then(setJournalDays).catch(() => {});
+  }, [journalEnabled]);
+  useEffect(() => {
+    reloadJournal();
+  }, [reloadJournal]);
+  // After typing, refresh which days have text (calendar dots) – at most every few seconds
+  const journalReloadTimer = useRef<number | null>(null);
+  const reloadJournalSoon = useCallback(() => {
+    if (journalReloadTimer.current !== null) return;
+    journalReloadTimer.current = window.setTimeout(() => {
+      journalReloadTimer.current = null;
+      reloadJournal();
+    }, 3000);
+  }, [reloadJournal]);
+  useEffect(() => () => {
+    if (journalReloadTimer.current !== null) window.clearTimeout(journalReloadTimer.current);
+  }, []);
+  const journalDocIds = useMemo(() => new Set(journalDays.map((d) => d.docId)), [journalDays]);
   const [selectedTag, setSelectedTag] = useState<string | null>(null);
   const [tagDetails, setTagDetails] = useState<TagDetails | null>(null);
   const [tagNoteDraft, setTagNoteDraft] = useState<string>('');
@@ -560,6 +592,34 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
     setMobileShowDetail(true);
   }, []);
 
+  const openJournalDay = useCallback(async (date: string): Promise<Document | null> => {
+    try {
+      const doc = await api.openJournalDay(date);
+      setDocs((prev) => (prev.some((d) => d.id === doc.id) ? prev : [doc, ...prev]));
+      setJournalDays((prev) =>
+        [
+          ...prev.filter((d) => d.date !== date),
+          { date, docId: doc.id, empty: !(doc.content || '').trim() },
+        ].sort((a, b) => b.date.localeCompare(a.date))
+      );
+      return doc;
+    } catch {
+      return null;
+    }
+  }, []);
+
+  const jumpToJournalDay = useCallback((date: string) => {
+    setJournalExtra((prev) => (prev.includes(date) ? prev : [...prev, date]));
+    setJournalActive(date);
+    setJournalJump({ date, nonce: Date.now() });
+  }, []);
+
+  const openJournal = useCallback(() => {
+    reloadJournal();
+    setSubView('journal');
+    setMobileShowDetail(true);
+  }, [reloadJournal]);
+
   const openTrash = useCallback(() => {
     reloadTrash();
     setSubView('trash');
@@ -939,6 +999,12 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
     }
   };
 
+  // Own journal notes appear under "Journal", not in the folder tree
+  const treeDocs = useMemo(
+    () => (journalDocIds.size ? docs.filter((d) => !(d.isOwner && journalDocIds.has(d.id))) : docs),
+    [docs, journalDocIds]
+  );
+
   const allFolderPaths = useMemo(() => {
     const set = new Set<string>(folders);
     for (const d of docs) {
@@ -977,7 +1043,7 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
       const sharedFolderObj = sharedFolders.find(
         (sf) => sf.mountPath === p || sf.name === p
       );
-      const folderDocs = docs.filter((d) => d.folderPath === p);
+      const folderDocs = treeDocs.filter((d) => d.folderPath === p);
 
       const node: FolderTreeNode = {
         name: leafName,
@@ -1002,16 +1068,16 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
     }
 
     return rootNodes;
-  }, [allFolderPaths, docs, sharedFolders]);
+  }, [allFolderPaths, treeDocs, sharedFolders]);
 
   const pinnedDocs = useMemo(
-    () => docs.filter((d) => d.isPinned),
-    [docs]
+    () => treeDocs.filter((d) => d.isPinned),
+    [treeDocs]
   );
 
   const rootDocs = useMemo(
-    () => docs.filter((d) => !d.folderPath && !d.isPinned),
-    [docs]
+    () => treeDocs.filter((d) => !d.folderPath && !d.isPinned),
+    [treeDocs]
   );
 
   // Global To-Dos rollup collections
@@ -1451,7 +1517,7 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
         {/* LEFT MASTER SIDEBAR */}
         <aside
           className={`${
-            (subView !== 'editor' && subView !== 'trash') || isSidebarCollapsed
+            (subView !== 'editor' && subView !== 'trash' && subView !== 'journal') || isSidebarCollapsed
               ? 'hidden'
               : mobileShowDetail
               ? 'hidden lg:flex'
@@ -1503,6 +1569,37 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
 
         {/* Scrollable Navigation Tree */}
         <div className="flex-1 overflow-y-auto p-2 space-y-3">
+          {/* Journal on top; while open, its calendar stays below it */}
+          {journalEnabled && (
+            <div className="border-b border-border pb-1.5 -mb-1.5">
+              <button
+                type="button"
+                onClick={openJournal}
+                className={`w-full flex items-center gap-2 px-2 h-11 sm:h-8 rounded-btn text-xs border transition-colors cursor-pointer ${
+                  subView === 'journal'
+                    ? 'bg-panel-elevated text-main font-semibold border-border/80'
+                    : 'border-transparent text-main hover:bg-panel-elevated'
+                }`}
+              >
+                <CalendarDays className="w-3.5 h-3.5 text-accent" />
+                <span className="flex-1 text-left">Journal</span>
+                {subView === 'journal' ? (
+                  <ChevronDown className="w-3.5 h-3.5 text-muted" />
+                ) : (
+                  <ChevronRight className="w-3.5 h-3.5 text-muted" />
+                )}
+              </button>
+              {subView === 'journal' && (
+                <div className="hidden lg:block px-1 pt-2 pb-1">
+                  <JournalCalendar
+                    activeDate={journalActive}
+                    entryDates={new Set(journalDays.filter((d) => !d.empty).map((d) => d.date))}
+                    onSelect={jumpToJournalDay}
+                  />
+                </div>
+              )}
+            </div>
+          )}
           {pinnedDocs.length === 0 && folderTree.length === 0 && rootDocs.length === 0 ? (
             <div className="px-2 py-2 text-xs text-muted">Noch keine Notizen</div>
           ) : (
@@ -1680,7 +1777,29 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
           subView !== 'editor' || mobileShowDetail || isSidebarCollapsed ? 'flex' : 'hidden lg:flex'
         } flex-1 flex-col min-w-0 h-full overflow-hidden bg-editor`}
       >
-        {subView === 'trash' ? (
+        {subView === 'journal' && journalEnabled ? (
+          <JournalView
+            days={journalDays}
+            extraDates={journalExtra}
+            activeDate={journalActive}
+            onActiveDateChange={setJournalActive}
+            jumpRequest={journalJump}
+            onOpenDay={openJournalDay}
+            onJump={jumpToJournalDay}
+            getDoc={(id) => docs.find((d) => d.id === id)}
+            currentUser={currentUser}
+            availableFolders={allFolderPaths}
+            onOpenShareModal={openDocShareModal}
+            onDocMetadataChange={handleDocMetadataChange}
+            onDeleteDoc={handleDeleteDocument}
+            onSelectTag={handleSelectTag}
+            onWikiLinkClick={handleWikiLinkClick}
+            onOpenDocBlock={handleJumpToDocBlock}
+            onOpenTask={onOpenTask}
+            onBackMobile={() => setMobileShowDetail(false)}
+            onDaySaved={reloadJournalSoon}
+          />
+        ) : subView === 'trash' ? (
           <TrashView
             items={trash}
             onOpen={handleOpenTrashedDoc}