feat(docker-watcher): phase 11 - frontend embed & SSE

Embed SvelteKit static build in Go binary via go:embed. Event bus
for pub/sub with deploy log, instance status, and deploy status events.
SSE endpoints for real-time streaming. Frontend SSE client with
exponential backoff reconnection. Makefile for build pipeline.
Update Phase 12 auth plan with OAuth2/OIDC support.

internal/api/router.go

@@ -4,6 +4,7 @@ import (
 	"github.com/go-chi/chi/v5"
 
 	"github.com/alexei/docker-watcher/internal/docker"
+	"github.com/alexei/docker-watcher/internal/events"
 	"github.com/alexei/docker-watcher/internal/store"
 	"github.com/alexei/docker-watcher/internal/webhook"
 )
@@ -14,6 +15,7 @@ type Server struct {
 	docker   *docker.Client
 	deployer DeployTriggerer
 	webhook  *webhook.Handler
+	eventBus *events.Bus
 	encKey   [32]byte
 }
 
@@ -23,6 +25,7 @@ func NewServer(
 	dockerClient *docker.Client,
 	deployer DeployTriggerer,
 	webhookHandler *webhook.Handler,
+	eventBus *events.Bus,
 	encKey [32]byte,
 ) *Server {
 	return &Server{
@@ -30,6 +33,7 @@ func NewServer(
 		docker:   dockerClient,
 		deployer: deployer,
 		webhook:  webhookHandler,
+		eventBus: eventBus,
 		encKey:   encKey,
 	}
 }
@@ -73,7 +77,10 @@ func (s *Server) Router() chi.Router {
 
 		// Deploy endpoints.
 		r.Get("/deploys", s.listDeploys)
-		r.Get("/deploys/{id}/logs", s.getDeployLogs)
+		r.Get("/deploys/{id}/logs", s.streamDeployLogs)
+
+		// SSE endpoint for real-time instance status and deploy events.
+		r.Get("/events", s.streamEvents)
 
 		// Quick deploy endpoints.
 		r.Post("/deploy/inspect", s.inspectImage)