feat(app): Home, the Library and the studyset sheets laid out as before

Home: plain cards on the surface, 16 dp apart, the goal first and the
Pomodoro timer after it in a new dashboard. The streak chip sits centred
in the app bar, and its sheet shows the days inside a big flame and the
week as marks over the weekdays' initials, with a word on today in a box.
The week names its day as "Thursday, Oct 8" and its days carry no
tooltip. The heatmap scrolls its weekdays with the weeks, outlines the
days to come, and names a day's activities with its date. The goal card
has a ring of 5 dp, a check once met and a pencil, and its sheet saves
across its width with Remove goal below. Arranging puts an eye on each
widget's corner and lifts the one picked up, with a tap the hand feels;
with every widget hidden, Customise brings arranging back. The stepper
moves to core, where the goal's sheet takes it too.

Library: the counts line includes files (PDFs); Refresh in the app bar
and pulling the list down sync now; a list that can't be read offers
Retry, which reads it again; the star keeps its square corners.

Studyset sheet: "Title *", the secondary title explained behind a
question mark, Inherit as a box beside the colour, and the description
in up to three lines with a chevron. Move sheet: round marks, the
studyset itself marked as current, the top level only while it is
inside another, archived studysets last under their heading, the
destination named in the footer, and a new studyset to move into, made
only once the move is.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

halkyon_learn_flutter/lib/l10n/app_de.arb

@@ -33,7 +33,7 @@
   "studysetSheetSave": "Speichern",
   "studysetSheetTitleLabel": "Titel",
   "studysetSheetSecondaryLabel": "Zweittitel",
-  "studysetSheetSecondaryHelper": "Wird als kleines Label über dem Titel angezeigt.",
+  "studysetSheetSecondaryHelper": "Wird als kleines Label über dem Titel auf Karten und im Kopf des Lernsets angezeigt. Pfade nutzen es, um Stufen zu kennzeichnen (Challenge, Meilenstein, Lektion).",
   "studysetSheetColor": "Farbe",
   "studysetSheetDiscardTitle": "Änderungen verwerfen?",
   "studysetSheetDiscardMessage": "Du hast ungespeicherte Änderungen an diesem Lernset. Verwerfen und das Formular schließen?",
@@ -44,6 +44,9 @@
 
   "studysetCountFlashcards": "{count, plural, =1{1 Karteikarte} other{{count} Karteikarten}}",
   "studysetCountNotes": "{count, plural, =1{1 Notiz} other{{count} Notizen}}",
+  "studysetCountFiles": "{count, plural, =1{1 Datei} other{{count} Dateien}}",
+  "libraryRefresh": "Aktualisieren",
+  "libraryRetry": "Erneut versuchen",
   "studysetNoContent": "Noch kein Inhalt",
   "studysetActionReview": "Wiederholen",
   "studysetActionStudy": "Lernen",
@@ -233,18 +236,25 @@
   "studysetDragToReorder": "Zum Umsortieren ziehen",
   "studysetMoveTitle": "Lernset verschieben nach",
   "studysetMoveTopLevel": "Oberste Ebene",
-  "studysetMoveCurrent": "Aktueller Ort",
+  "studysetMoveCurrent": "(aktuell)",
+  "studysetMoveTopLevelRow": "Oberste Ebene (in keinem Lernset)",
+  "studysetMoveArchived": "Archiviert",
+  "studysetMoveNew": "Neues Lernset",
+  "studysetMoveSelectDestination": "Wähle ein Ziel",
+  "studysetMoveDestination": "Ziel: {name}",
   "studysetMoveConfirm": "Verschieben",
-  "studysetMoveShowInside": "Inhalt anzeigen",
-  "studysetMoveHideInside": "Inhalt ausblenden",
-  "studysetMoved": "Nach „{destination}“ verschoben.",
+  "studysetMoveShowInside": "Unter-Lernsets anzeigen",
+  "studysetMoveHideInside": "Unter-Lernsets ausblenden",
+  "studysetMoved": "„{title}“ nach {destination} verschoben.",
   "studysetReadMore": "Mehr anzeigen",
   "studysetDescriptionTitle": "Beschreibung",
   "studysetDescriptionEditTitle": "Beschreibung bearbeiten",
   "richTextSave": "Speichern",
   "studysetSheetDescription": "Beschreibung",
-  "studysetSheetDescriptionAdd": "Beschreibung hinzufügen",
-  "studysetSheetInheritColor": "Gleiche Farbe wie das Lernset, in dem es liegt",
+  "studysetSheetDescriptionAdd": "Tippen, um eine Beschreibung hinzuzufügen",
+  "studysetSheetDescriptionAdded": "Beschreibung hinzugefügt — zum Bearbeiten tippen",
+  "studysetSheetInheritColor": "Erben",
+  "fieldRequired": "Pflichtfeld",
 
   "exploreTitle": "Entdecken",
   "exploreEmpty": "Lernsets, die andere teilen, erscheinen hier.",
@@ -602,8 +612,9 @@
   "homeShowWidget": "{label} anzeigen",
   "homeHideWidget": "{label} ausblenden",
   "homeAllHidden": "Alle Widgets sind ausgeblendet",
-  "homeAllHiddenHint": "Halte hier lange gedrückt, um welche zurückzuholen.",
-  "homeWidgetGoal": "Lernziel",
+  "homeAllHiddenBody": "Blende einige wieder ein, um dein Dashboard zu füllen.",
+  "homeCustomise": "Anpassen",
+  "homeWidgetGoal": "Tagesziel",
   "homeWidgetWeek": "Wochenübersicht",
   "homeWidgetActivity": "Aktivitäts-Heatmap",
   "homeActivityTitle": "Deine Aktivität",
@@ -635,11 +646,10 @@
   "weekPreviousDay": "Vorheriger Tag",
   "weekNextDay": "Nächster Tag",
   "weekRestDay": "Ruhetag",
-  "weekDueCount": "{count, plural, =1{1 Karte fällig} other{{count} Karten fällig}}",
   "heatmapLess": "Weniger",
   "heatmapMore": "Mehr",
   "heatmapTotal": "{count, plural, =1{1 Aktivität im letzten Jahr} other{{count} Aktivitäten im letzten Jahr}}",
-  "heatmapDay": "{count, plural, =0{Nichts} =1{1 Aktivität} other{{count} Aktivitäten}} · {date}",
+  "heatmapDay": "{count, plural, =1{1 Aktivität} other{{count} Aktivitäten}} · {date}",
 
   "commonCancel": "Abbrechen",
   "commonSave": "Speichern",
@@ -882,7 +892,7 @@
   "readerCaptureFailed": "Die Seite konnte nicht dargestellt werden. Versuche es erneut, sobald sie geladen ist.",
   "readerScreenshotSaved": "Bildschirmfoto gespeichert",
   "imageOpenPdfPage": "PDF auf dieser Seite öffnen",
-  "homeWidgetDeadlines": "Lesefristen",
+  "homeWidgetDeadlines": "PDF-Lesefristen",
   "deadlinesTitle": "Lesefristen",
   "deadlinesCurrent": "Aktuell",
   "deadlinesUpcoming": "Demnächst",