docs(09): complete phase planning

.planning/phases/09-task-creation-ux/09-CONTEXT.md

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+# Phase 9: Task Creation UX - Context
+
+**Gathered:** 2026-03-18
+**Status:** Ready for planning
+
+<domain>
+## Phase Boundary
+
+Rework the frequency picker from a flat grid of 10 preset ChoiceChips + hidden "Custom" mode into an intuitive "Every [N] [unit]" picker with quick-select shortcut chips. The picker is inherently freeform — no separate "Custom" mode. All existing interval types and calendar-anchored scheduling behavior must continue working. No new scheduling logic, no new DB columns, no new screens.
+
+</domain>
+
+<decisions>
+## Implementation Decisions
+
+### Picker layout
+- Shortcut chips first (compact row), then the "Every [N] [unit]" picker row below
+- Tapping a chip highlights it AND populates the picker row (bidirectional sync)
+- Editing the picker manually deselects any highlighted chip
+- Both always reflect the same value — single source of truth
+- The picker row is always visible, not hidden behind a "Custom" toggle
+
+### Number input
+- Keep the existing TextFormField with digit-only filter
+- Same pattern as the current custom interval input (TextFormField + FilteringTextInputFormatter.digitsOnly)
+- Minimum value: 1 (no max limit — if someone wants every 999 days, let them)
+- Text field centered, compact width (~60px as current)
+
+### Unit selector
+- Keep SegmentedButton with 3 units: Tage (days), Wochen (weeks), Monate (months)
+- No "years" unit — yearly is handled as 12 months in the picker
+- Consistent with existing SegmentedButton pattern used for effort level selector
+
+### Shortcut chips
+- 4 shortcut chips: Täglich, Wöchentlich, Alle 2 Wochen, Monatlich
+- No quarterly/yearly shortcut chips — users type 3/12 months via the freeform picker
+- Drop all other presets (every 2 days, every 3 days, every 2 months, every 6 months) — the freeform picker handles arbitrary intervals naturally
+- Chips use ChoiceChip widget (existing pattern)
+
+### Preset removal
+- Remove the entire `FrequencyInterval.presets` static list from being used in the UI
+- The 10-chip Wrap grid is fully replaced by 4 shortcut chips + freeform picker
+- The "Benutzerdefiniert" (Custom) chip is removed — the picker is inherently freeform
+- `_isCustomFrequency` boolean state is no longer needed
+
+### Edit mode behavior
+- When editing an existing task, match the stored interval to a shortcut chip if possible
+- Daily task → highlight "Täglich" chip, picker shows "Alle 1 Tage"
+- Weekly task → highlight "Wöchentlich" chip, picker shows "Alle 1 Wochen"
+- Biweekly → highlight "Alle 2 Wochen" chip, picker shows "Alle 2 Wochen"
+- Monthly → highlight "Monatlich" chip, picker shows "Alle 1 Monate"
+- Any other interval (e.g., every 5 days, quarterly, yearly) → no chip highlighted, picker filled with correct values
+
+### DB mapping
+- Shortcut chips map to existing IntervalType enum values (daily, weekly, biweekly, monthly)
+- Freeform days → IntervalType.everyNDays with the entered value
+- Freeform weeks → IntervalType.everyNDays with value * 7
+- Freeform months → IntervalType.everyNMonths with the entered value
+- Calendar-anchored behavior (anchorDay) preserved for month-based intervals
+- No changes to IntervalType enum, no new DB values, no migration needed
+
+### Claude's Discretion
+- Exact chip styling and spacing within the Wrap
+- Animation/transition when syncing chip ↔ picker
+- Whether the "Alle" prefix label is part of the picker row or omitted
+- How to handle the edge case where user clears the number field (empty → treat as 1)
+- l10n string changes needed for new/modified labels
+
+</decisions>
+
+<specifics>
+## Specific Ideas
+
+- User consistently prefers simplicity across phases ("just keep it simple" — Phase 8 pattern)
+- The key UX improvement: no more hunting through 10 chips or finding a hidden "Custom" mode — the picker is always there and always works
+- 4 common shortcuts for one-tap convenience, freeform picker for everything else
+- The current `_buildCustomFrequencyInput` method is essentially what becomes the primary picker — it already has the right structure
+
+</specifics>
+
+<code_context>
+## Existing Code Insights
+
+### Reusable Assets
+- `_buildCustomFrequencyInput()` in `task_form_screen.dart:279-326`: Already implements "Alle [N] [Tage|Wochen|Monate]" row with TextFormField + SegmentedButton — this becomes the primary picker
+- `_CustomUnit` enum (`task_form_screen.dart:511`): Already has days/weeks/months — reuse directly
+- `_customIntervalController` (`task_form_screen.dart:35`): Already exists for the number input
+- `_resolveFrequency()` (`task_form_screen.dart:378-415`): Already handles custom unit → IntervalType mapping — core logic stays the same
+- `_loadExistingTask()` (`task_form_screen.dart:55-101`): Already has edit-mode loading logic with preset matching — needs rework for new chip set
+- `FrequencyInterval.presets` (`frequency.dart:50-61`): Static list of 10 presets — UI no longer iterates this, but the model class stays for backward compat
+
+### Established Patterns
+- ChoiceChip in Wrap for multi-option selection (current frequency chips)
+- SegmentedButton for unit/level selection (effort level, custom unit)
+- TextFormField with FilteringTextInputFormatter for numeric input
+- ConsumerStatefulWidget with setState for form state management
+- German l10n strings in `app_de.arb` via `AppLocalizations`
+
+### Integration Points
+- `task_form_screen.dart`: Primary file — rework `_buildFrequencySelector()` method, simplify state variables
+- `frequency.dart`: `FrequencyInterval.presets` list is no longer iterated in UI but may still be used elsewhere (templates) — check before removing
+- `app_de.arb` / `app_localizations.dart`: May need new/updated l10n keys for shortcut chip labels
+- `template_picker_sheet.dart` / `task_templates.dart`: Templates create tasks with specific IntervalType values — no changes needed since DB mapping unchanged
+
+</code_context>
+
+<deferred>
+## Deferred Ideas
+
+None — discussion stayed within phase scope
+
+</deferred>
+
+---
+
+*Phase: 09-task-creation-ux*
+*Context gathered: 2026-03-18*