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/OutlinerTree.tsx

@@ -9,6 +9,8 @@ export interface OutlinerTreeHandle {
 
 export interface OutlinerTreeProps {
   docId: string;
+  /** Smaller click area below the last bullet (journal days) */
+  compact?: boolean;
   blocks: DocumentBlock[];
   canEdit: boolean;
   levelOffset?: number;
@@ -34,6 +36,7 @@ export interface OutlinerTreeProps {
 
 export const OutlinerTree = forwardRef<OutlinerTreeHandle, OutlinerTreeProps>(({
   docId,
+  compact = false,
   blocks,
   canEdit,
   levelOffset = 0,
@@ -810,7 +813,7 @@ export const OutlinerTree = forwardRef<OutlinerTreeHandle, OutlinerTreeProps>(({
 
       {canEdit && (
         <div
-          className={`min-h-[14rem] pt-2 pl-2 transition-colors cursor-text ${
+          className={`${compact ? 'min-h-[2.5rem]' : 'min-h-[14rem]'} pt-2 pl-2 transition-colors cursor-text ${
             dragOverIndex === blocks.length ? 'border-t-2 border-accent bg-accent/10 rounded' : ''
           }`}
           onClick={(e) => {