ci: remove temporary build check

.github/workflows/pr-check.yml

@@ -1,33 +0,0 @@
-name: PR build check (mqtt)
-
-# Baut den sensing-server mit aktiviertem mqtt-Feature, damit der
-# Per-Node-Discovery-Patch (#899) verifiziert wird.
-
-on:
-  push:
-    branches: [ "fix/per-node-mqtt-discovery" ]
-  pull_request:
-  workflow_dispatch:   # erlaubt manuelles Starten ueber den Actions-Tab
-
-jobs:
-  build:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-
-      - name: Install Rust toolchain
-        uses: dtolnay/rust-toolchain@stable
-
-      - name: Cache cargo
-        uses: Swatinem/rust-cache@v2
-        with:
-          workspaces: v2
-
-      - name: cargo check (mqtt feature)
-        working-directory: v2
-        run: cargo check -p wifi-densepose-sensing-server --features mqtt
-
-      - name: cargo build (mqtt feature)
-        working-directory: v2
-        run: cargo build -p wifi-densepose-sensing-server --features mqtt