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 +1,38 @@
+# rWallet — Treasury & Economics
+
+**Module ID:** `rwallet`
+**Domain:** `rwallet.online`
+**Version:** 0.1.0
+**Framework:** Static HTML/JS (Vanilla) — no server
+**Status:** Draft
+
+## Purpose
+
+Multichain wallet visualization and treasury management. Currently static frontend showing token holdings, Safe multisig balances, and flow diagrams. Future: Gnosis Safe integration for collaborative treasury governance.
+
+## Data Model
+
+Client-side only. Reads from blockchain APIs (Safe API, Etherscan, etc.).
+
+## Permission Model
+
+| Capability | Required SpaceRole | Description |
+|-----------|-------------------|-------------|
+| `view_treasury` | VIEWER | See wallet balances and flows |
+| `propose_transaction` | PARTICIPANT | Propose Safe transactions |
+| `approve_transaction` | PARTICIPANT | Sign/approve multisig txns |
+| `configure_treasury` | ADMIN | Add/remove Safe signers, change thresholds |
+
+**Current Auth:** None. Smart contract permissions govern on-chain actions.
+
+## Canvas Integration
+
+Shape types:
+- **`folk-token-mint`**: Token issuance widget
+- **`folk-token-ledger`**: Token distribution visualization
+
+## Migration Plan
+
+1. Add EncryptID for identity linking (DID ↔ wallet address)
+2. Space-level permissions for treasury dashboard access
+3. On-chain permissions remain contract-governed