Kurrent 0.2.0

Catch-up on the 1.0 branch: planner-style task flow, a full settings dialog, notifications, and a faster panel startup.

• Today no longer mixes overdue into “due today”; Catch-up (“Still open”) and an Overdue sidebar view
• Reschedule from the task row (15m / 1h / 4h / tomorrow / next week)
• Morning / afternoon / evening grouping and a list section field in the editor
• Join button for http(s) links; quick add (tomorrow 18:00 !high #tag)
• Completing a recurring task advances the series without dropping the RRULE
• Sort mode, catch-up, day-part hours, and Join persist in shared settings
• Settings shell: Appearance, Sidebar, Tasks, Editor, Panel, Notifications, Projects, and Labels pages; per-page reset; density and sidebar width tokens
• Settings forms use ConfigFormShell (centered, width-capped). SimpleKCM scrolls; no nested Flickable
• Shortcuts live in Plasma System Settings (no dedicated KCM); sync is manual (interval setting removed)
• Sidebar section/view order in settings via drag-and-drop
• Empty states for Akonadi offline, no calendars, and empty views
• One-step undo (complete / reschedule / move / delete), collapse subtask trees
• Panel badge (open / today / overdue) and flyout size; default due date; confirm row delete
• VALARM reminders in the editor, Plasma notifications with snooze, optional quiet hours
• Rename labels; complete parent can complete children; per-project and per-label color overrides
• Keyboard in the widget plus global Meta+Shift+K / Meta+Shift+N (D-Bus org.github.shrippen.Kurrent)
• Relative due chips
• Panel startup: non-blocking Akonadi start (ServerManager::start(), never Control::start()); cache can fill the badge/list immediately
• Compact panel icon first; FullView.qml (sidebar, list, editor) loads on first expand (preloadFullRepresentation: false)