docs(attachments): document task file attachments across project docs

Data/Worker/Ui CLAUDE.md + docs/open.md updated for TaskAttachmentEntity,
AttachmentStore, AttachmentMcpTools, AttachmentOrphanRecovery, the run-prompt
injection, and the detail-pane drag-and-drop UI (incl. a manual verification
item).

src/ClaudeDo.Ui/CLAUDE.md

@@ -36,7 +36,7 @@ Design/     — Tokens.axaml (design tokens; merged before styles) + IslandStyle
 - **IslandsShellViewModel** — root coordinator; owns the three island VMs and the `WorkerClient`, wires cross-island events (selection, notes/prep mode, conflict resolution), owns connection state, the update banner, the inline worker-log strip, responsive-layout flags (`ShowLists`/`ShowDetails` by window width), `PrimeStatus` flash, and the modal openers (About, RepoImport, WeeklyReport, WorktreesOverview, WorkerConnection help) plus `RestartWorkerAsync`/`CheckForUpdatesAsync`. Hosts `UpdateCheckService`.
 - **ListsIslandViewModel** — smart lists (My Day, Important, Planned, virtual queued/running/review), user lists, selection, list CRUD, drag-reorder, badge counts, opens list settings / repo import / worktrees overview, `OpenInExplorer`/`OpenInTerminal`.
 - **TasksIslandViewModel** — open/overdue/completed groups for the selected list with hierarchy-aware regrouping; task CRUD, drag-reorder, toggle done/star, schedule, enqueue/dequeue, cancel; review actions (approve, reject-rerun, reject-park, cancel); planning session lifecycle (open/resume/discard/finalize, `QueuePlanningSubtasksAsync`); `RunInteractivelyAsync`, `RefineTask`; MyDay extras (`IsMyDayList`, `ClearDayCommand`, `ShowPrepLogCommand`) and the pinned Notes pseudo-row (`ShowNotesRow`, `OpenNotesCommand`). Raises `NotesRequested`/`PrepRequested` events consumed by the shell.
-- **DetailsIslandViewModel** — the detail pane for a bound `TaskRowViewModel`. Owns live-log streaming (`Log` via `StreamLineFormatter`), debounced title/description editing, subtasks, session-outcome/roadblock split (splits `Result` at the roadblock marker into two cards), the three-tab work console (`output`/`git`/`session`), child surfacing (`ChildOutcomes` rows plus `ChildrenNeedingAttention`/`HasChildrenNeedingAttention` — children that failed, were cancelled, await review, or reported roadblocks — drive an attention band on the Session tab, which is only visible when `HasChildOutcomes`), and the modes: `IsNotesMode` (hosts `NotesEditorViewModel`), `IsPrepMode`, computed `IsTaskDetailVisible = !IsNotesMode && !IsPrepMode`. Three concerns are extracted into section VMs exposed as properties: **AgentSettingsSectionViewModel** (per-task Model/MaxTurns/AgentPath overrides with `InheritedBadge` + `InheritanceResolver`, additive SystemPrompt, debounced save), **MergeSectionViewModel** (merge-target selection, mergeability indicator via `MergePreviewPresenter` over `PreviewMergeAsync`, `OpenDiffAsync` — live worktree or commit range after merge —, `ReviewCombinedDiffCommand` → `PlanningDiffViewModel`), **PrepPanelViewModel** (daily-prep panel: `PrepLog`, `PlanDayCommand` → `RunDailyPrepNowAsync`, persisted last run via `GetLastPrepLogAsync`). Helper rows (`ChildOutcomeRowViewModel`, `SubtaskRowViewModel`, `LogLineViewModel`) live in the same file.
+- **DetailsIslandViewModel** — the detail pane for a bound `TaskRowViewModel`. Owns live-log streaming (`Log` via `StreamLineFormatter`), debounced title/description editing, subtasks, session-outcome/roadblock split (splits `Result` at the roadblock marker into two cards), the three-tab work console (`output`/`git`/`session`), child surfacing (`ChildOutcomes` rows plus `ChildrenNeedingAttention`/`HasChildrenNeedingAttention` — children that failed, were cancelled, await review, or reported roadblocks — drive an attention band on the Session tab, which is only visible when `HasChildOutcomes`), and the modes: `IsNotesMode` (hosts `NotesEditorViewModel`), `IsPrepMode`, computed `IsTaskDetailVisible = !IsNotesMode && !IsPrepMode`. Three concerns are extracted into section VMs exposed as properties: **AgentSettingsSectionViewModel** (per-task Model/MaxTurns/AgentPath overrides with `InheritedBadge` + `InheritanceResolver`, additive SystemPrompt, debounced save), **MergeSectionViewModel** (merge-target selection, mergeability indicator via `MergePreviewPresenter` over `PreviewMergeAsync`, `OpenDiffAsync` — live worktree or commit range after merge —, `ReviewCombinedDiffCommand` → `PlanningDiffViewModel`), **PrepPanelViewModel** (daily-prep panel: `PrepLog`, `PlanDayCommand` → `RunDailyPrepNowAsync`, persisted last run via `GetLastPrepLogAsync`). Attachments: `Attachments` (`ObservableCollection<AttachmentRowViewModel>`), `IsDragOver`, `DropStatus`, `CanAcceptDrop`, `AddFilesAsync`, `RemoveAttachmentCommand`; loads on task change; `ComposedPreview` includes attachment paths. Writes directly via `new AttachmentStore()` + `new TaskAttachmentRepository(ctx)`. Helper rows (`ChildOutcomeRowViewModel`, `SubtaskRowViewModel`, `LogLineViewModel`, `AttachmentRowViewModel`) live in the same file.
 - **TaskRowViewModel** / **ListNavItemViewModel** — lightweight display VMs (task row: status, planning phase, parent/blocked links, roadblock count, computed `IsDraft`/`IsPlanned`/`IsChild`/`IsPlanningParent`/`CanRefine`; list row: kind Smart/Virtual/User, count, icon/dot keys, drop hints).
 - **NotesEditorViewModel** — day navigator + bullet CRUD for daily notes via `INotesApi`.
 - **Modal VMs** — `SettingsModalViewModel` (four tabs: General, Worktrees, Files prompt-paths, Prime Claude incl. `DailyPrepMaxTasks` + prime-schedule rows), `ListSettingsModalViewModel` (name, working dir, commit type, per-list Model/SystemPrompt/AgentPath/MaxTurns with inherited-badge + reset, delete list), `RepoImportModalViewModel` (bulk-create lists from git repos found under chosen parents; already-wired repos disabled), `WeeklyReportModalViewModel` (range pickers default "since last standup weekday → today", cached per range, markdown via MarkdownView), `MergeModalViewModel` (single-task merge form, called from the diff modal), `WorktreesOverviewModalViewModel` (global/per-list worktree rows, batch merge + state ops), `UnfinishedPlanningModalViewModel` (Resume/FinalizeNow/Discard for a draft planning session), `WorkerConnectionModalViewModel` (offline help), `AboutModalViewModel`.
@@ -66,3 +66,4 @@ Modals use `TaskCompletionSource` results behind the reusable `ModalShell` contr
 - "Run Now" CanExecute re-evaluates when worker connection state changes
 - Icon gotcha: `PathIcon` fills geometry. Line-art/stroke icons must be defined as filled geometry or rendered as a stroked `Path` (e.g. `Icon.PlanDay` via the `Path.plan-icon` style); a pure stroke path used with `PathIcon` is invisible.
 - `SessionTerminalView` is the reusable log terminal (StyledProperties `Entries`, `Label`, `IsRunning`, `IsDone`, `IsFailed`) used for both the task `Log` and the prep `PrepLog`.
+- `DetailsIslandView` is a pane-wide drag-and-drop file target (`DragDrop.AllowDrop`, Avalonia 12 `DataFormat.File`) with a "Drop to attach" hover overlay. `DescriptionStepsCard` shows an Attachments list (file name, size, remove button), an "Add file…" picker, and an explicit `DropStatus` confirmation line. Keys use the `details.attachments.*` localization namespace (en + de).