docs: add MODULE_SPEC.md with permission model and capabilities

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

MODULE_SPEC.md

@@ -0,0 +1,37 @@
+# rCal — Temporal Coordination
+
+**Module ID:** `rcal`
+**Domain:** `rcal.online`
+**Version:** 0.1.0
+**Framework:** Next.js 14 / React 18 / Prisma / Leaflet / SunCalc / LunarPhase
+**Status:** Draft
+
+## Purpose
+
+Calendar and temporal coordination tool with alternative time systems — lunar phases, solar cycles, seasonal patterns. Integrates with Leaflet for location-aware time events and rSpace canvas for visual scheduling.
+
+## Data Model
+
+Prisma schema (PostgreSQL). Events, calendars, and time sources.
+
+## Permission Model
+
+| Capability | Required SpaceRole | Description |
+|-----------|-------------------|-------------|
+| `view_calendar` | VIEWER | See events and schedules |
+| `create_event` | PARTICIPANT | Add events to shared calendar |
+| `edit_own_events` | PARTICIPANT | Modify own events |
+| `moderate_events` | MODERATOR | Edit/delete others' events |
+| `configure_calendar` | ADMIN | Manage calendar settings, sources |
+
+**Current Auth:** None. Migration needed.
+
+## Canvas Integration
+
+Shape types: `folk-calendar-event`, `folk-timeline`
+
+## Migration Plan
+
+1. Add EncryptID auth middleware
+2. Add space concept to calendars
+3. Import SDK role types and capability maps