Drop embedded frontend from Pyroscope build

The webpack build fails on a @grafana/ui icons glob that doesn't
resolve in the Nix sandbox. Since Grafana is the primary UI via the
pyroscope datasource plugin, the standalone web UI isn't needed.
Build with EMBEDASSETS="" (upstream's build-dev path).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

containers/pyroscope/default.nix

@@ -2,6 +2,8 @@
 # Builds v1.19.1 from forge mirror
 # Uses stdenv + make (not buildGoModule) due to multi-module go.work workspace
 # with local replace directives (./api, ./lidia)
+# Built without embedded frontend — Grafana is the primary UI via the
+# grafana-pyroscope-datasource plugin, so the standalone web UI is not needed.
 # Built with dockerTools.buildLayeredImage for efficient layer caching
 { pkgs ? import <nixpkgs> { } }:
 
@@ -14,29 +16,6 @@ let
     hash = "sha256-UPxGimkzXLFACqmAM1hNQIoNjN6OquVibwVmNvP00+s=";
   };
 
-  # Build frontend assets via yarn + webpack (upstream uses Docker for this)
-  ui = pkgs.mkYarnPackage {
-    inherit version src;
-    pname = "pyroscope-ui";
-
-    buildPhase = ''
-      runHook preBuild
-      export HOME=$TMPDIR
-      cd deps/grafana-pyroscope
-      yarn --offline build
-      runHook postBuild
-    '';
-
-    installPhase = ''
-      runHook preInstall
-      mkdir -p $out
-      cp -r deps/grafana-pyroscope/public/build/* $out/
-      runHook postInstall
-    '';
-
-    distPhase = "true";
-  };
-
   # Pre-fetch Go modules for all go.mod files in the workspace (fixed-output derivation)
   goModules = pkgs.stdenv.mkDerivation {
     pname = "pyroscope-go-modules";
@@ -89,16 +68,11 @@ let
       cp -r ${goModules} $GOPATH/pkg/mod
       chmod -R u+w $GOPATH/pkg/mod
 
-      # Copy pre-built frontend assets
-      mkdir -p public/build
-      cp -r ${ui}/* public/build/
-
-      # Build Go binary with embedded frontend assets
-      # Skip the Makefile's frontend/build target (uses Docker) and
-      # invoke go/bin directly with EMBEDASSETS set
+      # Build Go binary without embedded frontend (EMBEDASSETS="")
+      # Grafana queries Pyroscope via API; standalone web UI not needed
       # CGO_ENABLED=0 for static binary (matches upstream)
       CGO_ENABLED=0 \
-        EMBEDASSETS=embedassets \
+        EMBEDASSETS="" \
         IMAGE_TAG=v${version} \
         make go/bin