ci: Add stress-test job to reproduce intermittent electrs failures

Run integration tests 10 times in a loop with --nocapture to maximize
the chance of hitting the intermittent electrs crash and to capture the
new diagnostic logging output.

AI tools were used in preparing this commit.

Author: joostjager

.github/workflows/rust.yml

@@ -86,6 +86,46 @@ jobs:
         run: |
           RUSTFLAGS="--cfg no_download --cfg cycle_tests" cargo test --features uniffi
 
+  stress-test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout source code
+        uses: actions/checkout@v3
+      - name: Install Rust stable toolchain
+        run: |
+          curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --profile=minimal --default-toolchain stable
+      - name: Enable caching for bitcoind
+        id: cache-bitcoind
+        uses: actions/cache@v4
+        with:
+          path: bin/bitcoind-${{ runner.os }}-${{ runner.arch }}
+          key: bitcoind-${{ runner.os }}-${{ runner.arch }}
+      - name: Enable caching for electrs
+        id: cache-electrs
+        uses: actions/cache@v4
+        with:
+          path: bin/electrs-${{ runner.os }}-${{ runner.arch }}
+          key: electrs-${{ runner.os }}-${{ runner.arch }}
+      - name: Download bitcoind/electrs
+        if: "steps.cache-bitcoind.outputs.cache-hit != 'true' || steps.cache-electrs.outputs.cache-hit != 'true'"
+        run: |
+          source ./scripts/download_bitcoind_electrs.sh
+          mkdir bin
+          mv "$BITCOIND_EXE" bin/bitcoind-${{ runner.os }}-${{ runner.arch }}
+          mv "$ELECTRS_EXE" bin/electrs-${{ runner.os }}-${{ runner.arch }}
+      - name: Set bitcoind/electrs environment variables
+        run: |
+          echo "BITCOIND_EXE=$( pwd )/bin/bitcoind-${{ runner.os }}-${{ runner.arch }}" >> "$GITHUB_ENV"
+          echo "ELECTRS_EXE=$( pwd )/bin/electrs-${{ runner.os }}-${{ runner.arch }}" >> "$GITHUB_ENV"
+      - name: Build integration tests
+        run: RUSTFLAGS="--cfg no_download --cfg cycle_tests" cargo test --test integration_tests_rust --no-run
+      - name: Stress-test integration tests (10 iterations)
+        run: |
+          for i in $(seq 1 10); do
+            echo "=== Iteration $i ==="
+            RUSTFLAGS="--cfg no_download --cfg cycle_tests" cargo test --test integration_tests_rust -- --nocapture 2>&1 || { echo "FAILED on iteration $i"; exit 1; }
+          done
+
   doc:
     name: Documentation
     runs-on: ubuntu-latest