Final sweep: Crucible fixes, Path Tracer polish, forge progress, tests green.

Align dashboard subtitle default and UpsertAgent tests with fleet label behavior; WebSocket coalesce and PathForge hardening; Crucible expanded ops and visual DV fixes; Vitest 610/610 and full test-suite pass; trim PROBLEMS.md to open items only.

server/internal/api/router.go

@@ -623,6 +623,7 @@ func NewRouter(database *db.Database, wsHub *WSHub, configHandler *ConfigHandler
 		if pathForgeHandler != nil {
 			r.Post("/builder/path-forge", pathForgeHandler.ServeHTTP)
 		}
+		r.Get("/builder/progress/{token}", builderHandler.ServeProgress)
 		r.Delete("/builder/cancel/{token}", func(w http.ResponseWriter, req *http.Request) {
 			token := chi.URLParam(req, "token")
 			if builderHandler.CancelBuild(token) {