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

node/explorer_assets.go

@@ -0,0 +1,166 @@
+package node
+
+import (
+	_ "embed"
+	"net/http"
+)
+
+//go:embed explorer/index.html
+var explorerIndexHTML string
+
+//go:embed explorer/address.html
+var explorerAddressHTML string
+
+//go:embed explorer/tx.html
+var explorerTxHTML string
+
+//go:embed explorer/node.html
+var explorerNodeHTML string
+
+//go:embed explorer/style.css
+var explorerStyleCSS string
+
+//go:embed explorer/common.js
+var explorerCommonJS string
+
+//go:embed explorer/app.js
+var explorerAppJS string
+
+//go:embed explorer/address.js
+var explorerAddressJS string
+
+//go:embed explorer/tx.js
+var explorerTxJS string
+
+//go:embed explorer/node.js
+var explorerNodeJS string
+
+//go:embed explorer/relays.html
+var explorerRelaysHTML string
+
+//go:embed explorer/relays.js
+var explorerRelaysJS string
+
+//go:embed explorer/validators.html
+var explorerValidatorsHTML string
+
+//go:embed explorer/validators.js
+var explorerValidatorsJS string
+
+//go:embed explorer/contract.html
+var explorerContractHTML string
+
+//go:embed explorer/contract.js
+var explorerContractJS string
+
+//go:embed explorer/tokens.html
+var explorerTokensHTML string
+
+//go:embed explorer/tokens.js
+var explorerTokensJS string
+
+//go:embed explorer/token.html
+var explorerTokenHTML string
+
+//go:embed explorer/token.js
+var explorerTokenJS string
+
+func serveExplorerIndex(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	_, _ = w.Write([]byte(explorerIndexHTML))
+}
+
+func serveExplorerAddressPage(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	_, _ = w.Write([]byte(explorerAddressHTML))
+}
+
+func serveExplorerTxPage(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	_, _ = w.Write([]byte(explorerTxHTML))
+}
+
+func serveExplorerNodePage(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	_, _ = w.Write([]byte(explorerNodeHTML))
+}
+
+func serveExplorerCSS(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "text/css; charset=utf-8")
+	_, _ = w.Write([]byte(explorerStyleCSS))
+}
+
+func serveExplorerCommonJS(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "application/javascript; charset=utf-8")
+	_, _ = w.Write([]byte(explorerCommonJS))
+}
+
+func serveExplorerJS(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "application/javascript; charset=utf-8")
+	_, _ = w.Write([]byte(explorerAppJS))
+}
+
+func serveExplorerAddressJS(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "application/javascript; charset=utf-8")
+	_, _ = w.Write([]byte(explorerAddressJS))
+}
+
+func serveExplorerTxJS(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "application/javascript; charset=utf-8")
+	_, _ = w.Write([]byte(explorerTxJS))
+}
+
+func serveExplorerNodeJS(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "application/javascript; charset=utf-8")
+	_, _ = w.Write([]byte(explorerNodeJS))
+}
+
+func serveExplorerRelaysPage(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	_, _ = w.Write([]byte(explorerRelaysHTML))
+}
+
+func serveExplorerRelaysJS(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "application/javascript; charset=utf-8")
+	_, _ = w.Write([]byte(explorerRelaysJS))
+}
+
+func serveExplorerValidatorsPage(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	_, _ = w.Write([]byte(explorerValidatorsHTML))
+}
+
+func serveExplorerValidatorsJS(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "application/javascript; charset=utf-8")
+	_, _ = w.Write([]byte(explorerValidatorsJS))
+}
+
+func serveExplorerContractPage(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	_, _ = w.Write([]byte(explorerContractHTML))
+}
+
+func serveExplorerContractJS(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "application/javascript; charset=utf-8")
+	_, _ = w.Write([]byte(explorerContractJS))
+}
+
+func serveExplorerTokensPage(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	_, _ = w.Write([]byte(explorerTokensHTML))
+}
+
+func serveExplorerTokensJS(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "application/javascript; charset=utf-8")
+	_, _ = w.Write([]byte(explorerTokensJS))
+}
+
+func serveExplorerTokenPage(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	_, _ = w.Write([]byte(explorerTokenHTML))
+}
+
+func serveExplorerTokenJS(w http.ResponseWriter, _ *http.Request) {
+	w.Header().Set("Content-Type", "application/javascript; charset=utf-8")
+	_, _ = w.Write([]byte(explorerTokenJS))
+}