Add system (curated) vs. user-uploaded flashcards

System decks/notes are owned by a reserved sentinel user id, reusing
all existing per-user store/index plumbing unchanged. Regular users
see them under a separate "Official Decks" section, can study them
with fully independent per-user FSRS progress (lazily materialized on
first visit), but can never edit or archive them - enforced both in
the client (no Edit/Archive controls) and server-side (ownership guard
on every mutating endpoint). Includes a small idempotent seed command
(`dotnet run -- seed-flashcards`) for testing, since there's no in-app
authoring UI yet.

scripts/ui/flashcards_hub.gd

@@ -31,6 +31,7 @@ var editor_overlay: Control
 var editor_panel: PanelContainer
 var editor_deck_label: Label
 var editor_note_id := ""
+var editor_target_deck_id := ""
 var editor_expected_revision: Variant = null
 var editor_type_selector: OptionButton
 var editor_front_input: TextEdit
@@ -333,10 +334,23 @@ func _on_decks_changed(loaded_decks: Array) -> void:
 	deck_ids = [""]
 	var total_due := 0
 	var total_new := 0
+	var my_decks := decks.filter(func(s): return not bool(s.get("deck", {}).get("isSystem", false)))
+	var official_decks := decks.filter(func(s): return bool(s.get("deck", {}).get("isSystem", false)))
+	if my_decks.size() > 0:
+		deck_selector.add_separator("My Decks")
+		deck_ids.append("")
+		for summary in my_decks:
+			var deck: Dictionary = summary.get("deck", {})
+			deck_selector.add_item(str(deck.get("name", "Deck")))
+			deck_ids.append(str(deck.get("id", "")))
+	if official_decks.size() > 0:
+		deck_selector.add_separator("Official Decks")
+		deck_ids.append("")
+		for summary in official_decks:
+			var deck: Dictionary = summary.get("deck", {})
+			deck_selector.add_item(str(deck.get("name", "Deck")))
+			deck_ids.append(str(deck.get("id", "")))
 	for summary in decks:
-		var deck: Dictionary = summary.get("deck", {})
-		deck_selector.add_item(str(deck.get("name", "Deck")))
-		deck_ids.append(str(deck.get("id", "")))
 		total_due += int(summary.get("due", 0))
 		total_new += int(summary.get("new", 0))
 	if previous_selection != null:
@@ -355,6 +369,16 @@ func _selected_deck_id() -> String:
 	return str(deck_ids[deck_selector.selected])
 
 
+func _is_system_deck(id: String) -> bool:
+	if id.is_empty():
+		return false
+	for summary in decks:
+		var deck: Dictionary = summary.get("deck", {})
+		if str(deck.get("id", "")) == id:
+			return bool(deck.get("isSystem", false))
+	return false
+
+
 func _reload_notes() -> void:
 	status_label.text = "Loading flashcards..."
 	var query := {
@@ -426,6 +450,13 @@ func _note_row(note: Dictionary) -> Control:
 	type_label.add_theme_font_size_override("font_size", 12)
 	type_label.add_theme_color_override("font_color", accent)
 	header_row.add_child(type_label)
+	var is_system := bool(note.get("isSystem", false))
+	if is_system:
+		var official_label := Label.new()
+		official_label.text = "Official"
+		official_label.add_theme_font_size_override("font_size", 12)
+		official_label.add_theme_color_override("font_color", Brand.PURPLE)
+		header_row.add_child(official_label)
 	var tags: Array = note.get("tags", [])
 	if tags.size() > 0:
 		var tags_label := Label.new()
@@ -446,25 +477,26 @@ func _note_row(note: Dictionary) -> Control:
 	actions.add_theme_constant_override("separation", 8)
 	row.add_child(actions)
 
-	var edit_button := Button.new()
-	edit_button.text = "Edit"
-	edit_button.custom_minimum_size = Vector2(70, 40)
-	edit_button.add_theme_stylebox_override("normal", Brand.secondary_button_box(dark))
-	edit_button.add_theme_stylebox_override("hover", Brand.secondary_button_box(dark, true))
-	edit_button.pressed.connect(_open_editor.bind(str(note.get("id", "")), note))
-	actions.add_child(edit_button)
+	if not is_system:
+		var edit_button := Button.new()
+		edit_button.text = "Edit"
+		edit_button.custom_minimum_size = Vector2(70, 40)
+		edit_button.add_theme_stylebox_override("normal", Brand.secondary_button_box(dark))
+		edit_button.add_theme_stylebox_override("hover", Brand.secondary_button_box(dark, true))
+		edit_button.pressed.connect(_open_editor.bind(str(note.get("id", "")), note))
+		actions.add_child(edit_button)
 
-	var archive_button := Button.new()
-	archive_button.text = "Archive"
-	archive_button.custom_minimum_size = Vector2(85, 40)
-	archive_button.add_theme_stylebox_override("normal", Brand.secondary_button_box(dark))
-	archive_button.add_theme_stylebox_override("hover", Brand.secondary_button_box(dark, true))
-	archive_button.add_theme_color_override("font_color", Color("ff5f76") if dark else Color("be123c"))
-	archive_button.pressed.connect(func():
-		FlashcardService.archive_notes([str(note.get("id", ""))], true)
-		await get_tree().create_timer(0.3).timeout
-		_reload_notes())
-	actions.add_child(archive_button)
+		var archive_button := Button.new()
+		archive_button.text = "Archive"
+		archive_button.custom_minimum_size = Vector2(85, 40)
+		archive_button.add_theme_stylebox_override("normal", Brand.secondary_button_box(dark))
+		archive_button.add_theme_stylebox_override("hover", Brand.secondary_button_box(dark, true))
+		archive_button.add_theme_color_override("font_color", Color("ff5f76") if dark else Color("be123c"))
+		archive_button.pressed.connect(func():
+			FlashcardService.archive_notes([str(note.get("id", ""))], true)
+			await get_tree().create_timer(0.3).timeout
+			_reload_notes())
+		actions.add_child(archive_button)
 
 	return row
 
@@ -594,7 +626,11 @@ func _open_editor(note_id: String, note: Dictionary) -> void:
 	editor_extra_input.text = str(note.get("extra", ""))
 	editor_tags_input.text = ", ".join(PackedStringArray(note.get("tags", [])))
 	editor_error_label.visible = false
-	editor_deck_label.text = "Saving to: %s" % _deck_name_for_id(str(note.get("deckId", "")) if not note_id.is_empty() else _selected_deck_id())
+	if note_id.is_empty():
+		editor_target_deck_id = "" if _is_system_deck(_selected_deck_id()) else _selected_deck_id()
+	else:
+		editor_target_deck_id = str(note.get("deckId", ""))
+	editor_deck_label.text = "Saving to: %s" % _deck_name_for_id(editor_target_deck_id)
 	_on_editor_type_changed(editor_type_selector.selected)
 	editor_overlay.visible = true
 
@@ -629,7 +665,7 @@ func _save_editor() -> void:
 		if not trimmed.is_empty():
 			tags.append(trimmed)
 	var payload := {
-		"deckId": _selected_deck_id(),
+		"deckId": editor_target_deck_id,
 		"stableId": "",
 		"type": "cloze" if is_cloze else "basic",
 		"prompt": prompt,

scripts/ui/flashcards_study.gd

@@ -72,6 +72,7 @@ var compact_layout := false
 
 var deck_panel: PanelContainer
 var deck_name_label: Label
+var deck_system_badge: Label
 var deck_ring: Control
 var deck_mastered_label: Label
 var change_deck_button: Button
@@ -371,6 +372,13 @@ func _build_deck_panel() -> void:
 	deck_name_label.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
 	content.add_child(deck_name_label)
 
+	deck_system_badge = Label.new()
+	deck_system_badge.text = "Official Deck"
+	deck_system_badge.add_theme_font_size_override("font_size", 12)
+	deck_system_badge.add_theme_color_override("font_color", Brand.PURPLE)
+	deck_system_badge.visible = false
+	content.add_child(deck_system_badge)
+
 	var ring_center := CenterContainer.new()
 	content.add_child(ring_center)
 	deck_ring = CircularProgress.new()
@@ -597,6 +605,7 @@ func _refresh_deck_panel() -> void:
 	var name := "All decks"
 	var total := 0
 	var mastered := 0
+	var is_system := false
 	if deck_id.is_empty():
 		for summary in decks:
 			total += int(summary.get("total", 0))
@@ -608,8 +617,10 @@ func _refresh_deck_panel() -> void:
 				name = str(deck.get("name", "Deck"))
 				total = int(summary.get("total", 0))
 				mastered = int(summary.get("mastered", 0))
+				is_system = bool(deck.get("isSystem", false))
 				break
 	deck_name_label.text = name
+	deck_system_badge.visible = is_system
 	var fraction := float(mastered) / float(total) if total > 0 else 0.0
 	deck_ring.configure(fraction, "%d%%" % roundi(fraction * 100.0), "Mastery", Brand.ROYAL_BLUE, dark)
 	deck_mastered_label.text = "%d / %d cards mastered" % [mastered, total]