chore: complete v1.2 milestone — archive roadmap, requirements, update retrospective

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

.planning/RETROSPECTIVE.md

@@ -90,6 +90,50 @@
 
 ---
 
+## Milestone: v1.2 — Polish & Task Management
+
+**Shipped:** 2026-04-03
+**Phases:** 4 | **Plans:** 6
+
+### What Was Built
+- Smart task delete: hard-delete for unused tasks, soft-delete (isActive flag) for tasks with history
+- Reworked frequency picker: 4 shortcut chips + freeform "Every N unit" interface
+- Dead code cleanup: 3 orphaned v1.0 files removed, zero regressions
+- Anytime task completion: checkboxes always enabled, nextDueDate recalculated from today
+- Recurring task pre-population: virtual instances on all interval days with 0.55 opacity muted styling
+- "Demnächst" (upcoming) section in calendar day view for pre-populated tasks
+
+### What Worked
+- Drift schema migration pattern (v2→v3 with BoolColumn.withDefault) was clean — existing rows auto-migrated
+- Query-time virtual instances for pre-population avoided a schema migration entirely — provider-layer only
+- Phase 10 cleanup was surgical: 3 files deleted, DailyPlanDao preserved, all 144 tests passed
+- TDD continued to work well — 9 new DAO tests for pre-population queries caught edge cases
+- Plan 11-01 was small and focused (remove restrictions + fix recalculation) — executed quickly
+
+### What Was Inefficient
+- Phase 11 split across two sessions due to scope — could have been planned as a single phase with tighter scope
+- Flutter/dart not available in CI-less environment — verification gate always needs human testing for visual/runtime items
+- _subtractMonths year-boundary bug was caught during execution — the plan's formula used Dart truncation division which fails for negative month values
+
+### Patterns Established
+- isActive BoolColumn.withDefault(true) for soft-delete with auto-migration
+- _ShortcutFrequency enum with bidirectional toPickerValues()/fromPickerValues() for picker ↔ shortcut sync
+- Interval-window pre-population: query all recurring tasks, filter by `_isInCurrentIntervalWindow`, exclude completed-in-period
+- Total-month arithmetic for _subtractMonths: `totalMonths = year*12 + month - N` avoids Dart truncation division pitfall
+
+### Key Lessons
+1. Provider-layer virtual instances are a powerful pattern for showing derived data without schema changes
+2. Dart's integer truncation division (`~/`) behaves differently from floor division for negative values — always test boundary cases
+3. Soft-delete with BoolColumn.withDefault is the cleanest Drift migration pattern — no backfill needed
+4. Small focused plans (11-01: 2 tasks, 4 files) execute faster and more reliably than large plans
+
+### Cost Observations
+- Model mix: orchestrator on opus, executors/verifiers on sonnet
+- Sessions: 2 (plan 01 in prior session, plan 02 + verification in this session)
+- Notable: Plan 11-02 was the most complex single plan in v1.2 — 6 files, 3 new DAO methods, provider rewrite, UI changes
+
+---
+
 ## Cross-Milestone Trends
 
 ### Process Evolution
@@ -98,16 +142,19 @@
 |-----------|--------|-------|------------|
 | v1.0 | 4 | 13 | Initial project — established all patterns |
 | v1.1 | 3 | 5 | Reused v1.0 patterns — faster execution, auto-advance mode |
+| v1.2 | 4 | 6 | Schema migration, provider-layer virtual instances, soft-delete pattern |
 
 ### Cumulative Quality
 
-| Milestone | Tests | LOC (lib) | Key Metric |
-|-----------|-------|-----------|------------|
-| v1.0 | 89 | 7,773 | dart analyze clean, 0 issues |
-| v1.1 | 108 | 9,051 | dart analyze clean, 0 issues |
+| Milestone | Tests | LOC (total) | Key Metric |
+|-----------|-------|-------------|------------|
+| v1.0 | 89 | 7,773 (lib) | dart analyze clean, 0 issues |
+| v1.1 | 108 | 9,051 (lib) | dart analyze clean, 0 issues |
+| v1.2 | 117+ | 13,232 (lib+test) | Drift schema v3, 14 requirements |
 
 ### Top Lessons (Verified Across Milestones)
 
 1. **Research must verify current package API signatures** — v1.0 hit riverpod_generator type incompatibility, v1.1 hit StateProvider removal. Same root cause: outdated API assumptions in plans.
-2. **Established patterns compound** — v1.1 plans averaged ~5 min vs v1.0's ~6 min. Reusing DAO, provider, and test patterns eliminated design decisions.
-3. **Verification gates are cheap insurance** — Consistently ~2 min per phase, caught regressions in both milestones.
+2. **Established patterns compound** — v1.1 plans averaged ~5 min vs v1.0's ~6 min. v1.2 reused all established patterns seamlessly.
+3. **Verification gates are cheap insurance** — Consistently ~2 min per phase, caught regressions in all milestones.
+4. **Provider-layer transformations avoid schema migrations** — v1.2's pre-population used query-time virtual instances, proving complex derived views can live entirely in the provider layer.