docs: add .planning/ project-tracking documents

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.planning/PROJECT.md

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+# Calendula
+
+## What This Is
+
+A modern Material 3 Expressive Android calendar app, read-only V1. Lives
+entirely on top of Android's `CalendarContract` — any calendar synced to the
+device (CalDAV via DAVx5, Google, local, WebCal, …) shows up automatically.
+The differentiator is visual: real Material 3 Expressive design that no
+existing FOSS calendar app delivers.
+
+## Core Value
+
+A calendar app that is genuinely pleasant to look at and use, without
+re-inventing the calendar sync stack — leave that to DAVx5 and the system.
+
+## Current Milestone
+
+**v0.1 — Foundation & CI:** Buildable Android project scaffold with theme,
+icon, i18n, Hilt, DataStore, green CI.
+
+## Stack
+
+Kotlin 2.3, Jetpack Compose + Material 3 Expressive (alpha for 1.5 APIs),
+Hilt, DataStore. Gradle Kotlin DSL with Version Catalog. AGP 9.1, Gradle 9.5.
+
+Read-only V1, write support V2.
+
+Android-only (minSdk 29, targetSdk 36). No iOS.
+
+## Naming
+
+"Calendula" — Latin *kalendae* ("first day of the month", root of "calendar")
+is also the etymological root of the marigold flower Calendula. The icon
+shows a stylized "1" on a slate squircle.
+
+## Source
+
+Hosted on self-hosted Gitea, released through self-hosted F-Droid repo on
+Hetzner. Same infrastructure as `HouseHoldKeaper`.

.planning/REQUIREMENTS.md

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+# Calendula — Requirements
+
+See full design spec: `docs/superpowers/specs/2026-06-08-calendar-app-design.md`
+
+## V1 Scope (Variant "B")
+
+### Validated (shipped)
+- (none yet — first milestone in progress)
+
+### Active (V1)
+
+- [ ] Foundation & CI infrastructure
+- [ ] Data Layer over `CalendarContract`
+- [ ] Permission flow (`READ_CALENDAR`)
+- [ ] Month view (S1)
+- [ ] Week view (S2)
+- [ ] Day view (S3)
+- [ ] Event Detail Sheet (S4)
+- [ ] Multi-Calendar Filter (M3)
+- [ ] Today button + Jump-to-Date (M2)
+- [ ] View-Switcher (M1)
+- [ ] Settings screen (M4)
+- [ ] Empty / no-permission / no-calendars states
+- [ ] German + English localization
+- [ ] Loading/Failure/Success states per screen (architectural pattern)
+
+### Out of Scope (V2+)
+
+- Event create / edit / delete (V2)
+- Home-screen widget
+- Full-text search
+- Quick-add
+- Custom notifications/reminders (system already handles these)
+- Tablet/foldable-specific layouts
+- iOS support (Android-only by design)
+
+## Constraints
+
+- **Tech stack:** Kotlin + Jetpack Compose + Material 3 Expressive, Hilt, DataStore
+- **Platform:** Android 10+ (API 29 minimum), Android 16 (API 36) target
+- **Offline-first:** all data lives in `CalendarContract`; no app-side network
+- **Privacy:** zero telemetry, no analytics
+- **i18n:** German + English from day one
+- **Tests + CI from day one**
+- **License:** MIT

.planning/ROADMAP.md

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+# Calendula — Roadmap
+
+## v0.x — Pre-Release
+
+| Version | Milestone | Status |
+|---|---|---|
+| v0.1 | Foundation & CI | in progress |
+| v0.2 | Data Layer & Permission Flow | pending |
+| v0.3 | Month view | pending |
+| v0.4 | Week view | pending |
+| v0.5 | Day view | pending |
+| v0.6 | Event Detail Sheet | pending |
+| v0.7 | Filter & Settings | pending |
+
+## v1.0 — First Public Release
+
+All V1 features shipped, polished, on F-Droid. Read-only calendar.
+
+## v2.0 — Write Support
+
+- Event create / edit / delete via `CalendarContract` writes
+- Quick-add sheet
+- Conflict UX (event modified externally during edit)
+
+## v3.0 — Power-User Features
+
+- Home-screen widget
+- Full-text search
+- Tablet / foldable layouts
+- Optional: ICS file import (drag-and-drop)
+
+Order is indicative — community feedback after V1 may re-prioritize.

.planning/STATE.md

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+# Calendula — Current State
+
+*Last updated: 2026-06-08*
+
+## Status
+
+**Milestone:** v0.1 — Foundation & CI
+**Phase:** Implementation in progress (Plan 01 active)
+
+## Progress
+
+- [x] Design spec written and committed (`docs/superpowers/specs/2026-06-08-calendar-app-design.md`)
+- [x] V1 design decisions resolved (App name "Calendula", icon, seed color)
+- [x] Plan 01 written (`docs/superpowers/plans/2026-06-08-01-foundation.md`)
+- [ ] Plan 01 executed
+
+## Next
+
+1. Execute Plan 01 to land foundation
+2. Write and execute Plan 02 (Data Layer & Permission Flow)
+3. Iterate on UI design (mockups) before screens are built