docs: add .planning/ project-tracking documents

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

.planning/ROADMAP.md

@@ -0,0 +1,32 @@
+# 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.