docs: update CLAUDE.md and PLAN.md for Phase 3 progress

Mark completed features: move task, rename list, due date picker,
group-by-due-date toggle, keyboard shortcuts, WebDAV credentials
flow, file watcher. Update current state date, add Flutter GUI to
architecture section, revise remaining TODO list.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -32,6 +32,7 @@ Two-crate workspace (`resolver = "2"`, edition 2021) plus a Tauri app:
 - **onyx-core** — Pure Rust library. Storage trait with `FileSystemStorage` implementation, `TaskRepository` (main API), data models, config, error types. No CLI/UI dependencies.
 - **onyx-cli** — CLI frontend using clap. Commands are in `src/commands/` (init, workspace, list, task, group). Output formatting in `src/output.rs`.
 - **apps/tauri/** — Tauri v2 GUI. Svelte 5 frontend in `src/`, Rust backend in `src-tauri/` with Tauri commands that call into `onyx-core`.
+- **apps/flutter/** — Flutter GUI. Dart frontend in `lib/src/`, Rust backend in `rust/` via flutter_rust_bridge FFI into `onyx-core`.
 
 ### Key patterns
 
@@ -55,11 +56,11 @@ The GUI uses Svelte 5 runes mode (`$state`, `$derived`, `$effect`, `$props()`).
 - **Kebab menus**: Tasks, lists, and workspaces all use kebab → submenu pattern for delete.
 - **New task**: FAB button opens bottom toast sheet (outside sliding container for fixed positioning).
 
-### Current state (2026-03-30)
+### Current state (2026-03-31)
 
 - **Phase 1** (Core + CLI): Complete
-- **Phase 2** (WebDAV sync): Backend done, CLI done, GUI partially wired (empty credentials issue)
-- **Phase 3** (GUI MVP): In progress — core task CRUD working, UI polished with animations
+- **Phase 2** (WebDAV sync): Backend done, CLI done, GUI wired (settings auto-populates credentials)
+- **Phase 3** (GUI MVP): Near complete — core features working, both Tauri and Flutter GUIs maintained
 
 ### GUI features done
 
@@ -72,17 +73,23 @@ The GUI uses Svelte 5 runes mode (`$state`, `$derived`, `$effect`, `$props()`).
 - Workspace switcher drop-up with add/remove
 - Dark mode (GNOME-style neutral grays, cyan-blue accent)
 - Completed tasks section with animated show/hide
+- Due date picker/editor (DateTimePicker in new task + task detail)
+- Move task between lists (kebab menu → "Move to..." submenu)
+- List rename (inline input via list kebab menu)
+- Group-by-due-date toggle per list (list kebab menu)
+- Keyboard shortcuts (Escape priority chain: settings → detail → drawer → menus)
+- WebDAV setup flow (settings auto-populates URL/credentials from config + keychain)
+- File watcher (notify crate, 500ms debounce, auto-reloads on external changes)
+- Setup screen with window dragging + "Open Existing Folder" option
 
-### GUI features NOT yet done (CLI has these)
+### GUI features NOT yet done
 
-- Due date editing (model supports it, not exposed in UI)
-- WebDAV setup flow (GUI passes empty credentials)
 - Push-only / pull-only sync modes
-- Sync status view
+- Sync status view/indicators
 - Workspace retarget/migrate
-- Group-by-due-date toggle
 - Subtask hierarchy (data model exists, not used anywhere)
-- List/workspace rename
+- Search/filter tasks
+- Desktop packaging (Windows, Linux, macOS)
 
 ## Roadmap
 

PLAN.md

@@ -715,18 +715,19 @@ WorkspaceConfig {
 - [x] Settings popup overlay (WebDAV config, dark mode toggle)
 - [x] Dark mode (GNOME-style neutral theme, cyan-blue accent)
 - [x] Animated completed section show/hide
-- [ ] Move task between lists (needs `move_task(from_list, to_list, task_id)` added to onyx-core + Tauri command, then wire into task detail kebab menu)
+- [x] Move task between lists (kebab menu → "Move to..." submenu in task detail view)
 - [ ] Optional time on due dates (backend `due_date` is `DateTime<Utc>` — needs a separate `due_time` field or a nullable time component so date-only tasks don't default to midnight; currently the GUI uses `hours == 0 && minutes == 0` as a heuristic for "no time set" which breaks for actual midnight times)
-- [ ] Due date picker/editor (backend supports it, needs date input in new task toast + inline editing)
-- [ ] WebDAV setup flow with credentials (settings panel has fields, triggerSync needs to pull creds from config)
-- [ ] List/workspace rename (needs `rename_list` added to onyx-core first)
-- [ ] Keyboard shortcuts (Escape to close drawers/menus, tab navigation, Enter behaviors)
+- [x] Due date picker/editor (DateTimePicker component in both new task toast + task detail view)
+- [x] WebDAV setup flow with credentials (settings auto-populates URL/username/password from config + keychain on open)
+- [x] List rename (inline input via list kebab menu in drawer)
+- [x] Keyboard shortcuts (Escape closes settings → detail → drawer → menus in priority order)
 - [ ] Sync status indicators (per workspace)
 - [ ] Push/pull sync mode selection
-- [ ] Group-by-due-date toggle per list
+- [x] Group-by-due-date toggle per list (checkmark toggle in list kebab menu)
 - [ ] Subtask hierarchy (data model exists, needs UI)
 - [ ] Search/filter tasks
 - [ ] Desktop packaging (Windows, Linux, macOS)
+- [x] File watcher (notify crate, 500ms debounce, auto-reloads UI on external file changes)
 
 ### Deliverables