Phase 3: Svelte 5 UI skeleton

Svelte 5 + Vite + TypeScript dashboard that consumes kamado-api over
REST for the first paint and then subscribes to /api/ws for live
updates. Zero runtime deps beyond svelte itself; plain CSS, no
component library.

Layout:

- Header with brand, WebSocket status badge, chain + height
- PoolOverview: hashrate (1m/5m/1h/24h), miner count, network
  hashrate + diff, pool share (ppb), expected time to block, uptime
- BlocksTable: recent solves from the in-memory ring (will be
  SQLite-backed in Phase 2b.5)
- BestShares: top-10 workers by bestever, falling back to bestdiff
  when the ckpool patch isn't present
- MinersTable: joined view of stratum clients and workers with
  user-agent-based hardware detection (Bitaxe, NerdQAxe, Antminer,
  ...), hashrate, best-round, best-ever, last share

State is a single $state() snapshot store in svelte-runes form;
components read from it via $derived. The store does one initial
REST snapshot fetch, then owns the WebSocket with exponential
backoff reconnects.

Vite dev server on :5173 proxies /api and /api/ws to localhost:8080
so you can run `make ui-dev` alongside `make up` in development.
Production serving (bundled into the Go binary via embed, behind /
on :8080) lands in Phase 4.

Makefile

@@ -1,13 +1,16 @@
 # ----------------------------------------------------------------------------
 # Kamado Pool — top-level Makefile
 # ----------------------------------------------------------------------------
-.PHONY: help ckpool api api-test ckpool-shell up down logs clean
+.PHONY: help ckpool api api-test ckpool-shell ui ui-dev ui-check up down logs clean
 
 help:
 	@echo "Kamado Pool targets:"
 	@echo "  make ckpool        Build the ckpool-solo docker image"
 	@echo "  make api           Build the kamado-api docker image"
 	@echo "  make api-test      Run Go tests for kamado-api (requires Go installed)"
+	@echo "  make ui            Build the Svelte UI to ui/dist (requires node)"
+	@echo "  make ui-dev        Run the Vite dev server on :5173 with /api proxy"
+	@echo "  make ui-check      Run svelte-check type diagnostics"
 	@echo "  make ckpool-shell  Open a shell in the built ckpool image"
 	@echo "  make up            docker compose up -d --build"
 	@echo "  make down          docker compose down"
@@ -23,6 +26,15 @@ api:
 api-test:
 	cd api && go test ./... -race
 
+ui:
+	cd ui && npm install && npm run build
+
+ui-dev:
+	cd ui && npm install && npm run dev
+
+ui-check:
+	cd ui && npm install && npm run check
+
 ckpool-shell: ckpool
 	docker run --rm -it --entrypoint /bin/sh kamado/ckpool:dev