chore: initial commit for v0.0.1

DChain single-node blockchain + React Native messenger client.

Core:
- PBFT consensus with multi-sig validator admission + equivocation slashing
- BadgerDB + schema migration scaffold (CurrentSchemaVersion=0)
- libp2p gossipsub (tx/v1, blocks/v1, relay/v1, version/v1)
- Native Go contracts (username_registry) alongside WASM (wazero)
- WebSocket gateway with topic-based fanout + Ed25519-nonce auth
- Relay mailbox with NaCl envelope encryption (X25519 + Ed25519)
- Prometheus /metrics, per-IP rate limit, body-size cap

Deployment:
- Single-node compose (deploy/single/) with Caddy TLS + optional Prometheus
- 3-node dev compose (docker-compose.yml) with mocked internet topology
- 3-validator prod compose (deploy/prod/) for federation
- Auto-update from Gitea via /api/update-check + systemd timer
- Build-time version injection (ldflags → node --version)
- UI / Swagger toggle flags (DCHAIN_DISABLE_UI, DCHAIN_DISABLE_SWAGGER)

Client (client-app/):
- Expo / React Native / NativeWind
- E2E NaCl encryption, typing indicator, contact requests
- Auto-discovery of canonical contracts, chain_id aware, WS reconnect on node switch

Documentation:
- README.md, CHANGELOG.md, CONTEXT.md
- deploy/single/README.md with 6 operator scenarios
- deploy/UPDATE_STRATEGY.md with 4-layer forward-compat design
- docs/contracts/*.md per contract

contracts/escrow/escrow_abi.json

@@ -0,0 +1,57 @@
+{
+  "contract": "escrow",
+  "version": "1.0.0",
+  "description": "Two-party trustless escrow. Buyer deposits funds into the contract treasury. Seller delivers; buyer releases. If disputed, the contract admin resolves.",
+  "methods": [
+    {
+      "name": "init",
+      "description": "Set the caller as the escrow admin. Call once after deployment.",
+      "args": []
+    },
+    {
+      "name": "create",
+      "description": "Buyer creates an escrow. Transfers amount from buyer to treasury. Logs 'created: <id>'.",
+      "args": [
+        {"name": "id",     "type": "string", "description": "Unique escrow ID (user-supplied)"},
+        {"name": "seller", "type": "string", "description": "Seller address (hex pubkey)"},
+        {"name": "amount", "type": "uint64", "description": "Amount in µT to lock in escrow"}
+      ]
+    },
+    {
+      "name": "release",
+      "description": "Buyer releases funds to seller. Transfers treasury → seller. Logs 'released: <id>'.",
+      "args": [
+        {"name": "id", "type": "string", "description": "Escrow ID"}
+      ]
+    },
+    {
+      "name": "refund",
+      "description": "Seller refunds the buyer (voluntary). Transfers treasury → buyer. Logs 'refunded: <id>'.",
+      "args": [
+        {"name": "id", "type": "string", "description": "Escrow ID"}
+      ]
+    },
+    {
+      "name": "dispute",
+      "description": "Buyer or seller raises a dispute. Logs 'disputed: <id>'. Admin must then call resolve.",
+      "args": [
+        {"name": "id", "type": "string", "description": "Escrow ID"}
+      ]
+    },
+    {
+      "name": "resolve",
+      "description": "Admin resolves a disputed escrow. winner must be 'buyer' or 'seller'. Logs 'resolved: <id>'.",
+      "args": [
+        {"name": "id",     "type": "string", "description": "Escrow ID"},
+        {"name": "winner", "type": "string", "description": "'buyer' or 'seller'"}
+      ]
+    },
+    {
+      "name": "info",
+      "description": "Log escrow details: buyer, seller, amount, status.",
+      "args": [
+        {"name": "id", "type": "string", "description": "Escrow ID"}
+      ]
+    }
+  ]
+}