[ci] Summarize the management unit test stream in the Linux workflow

Run the Management / Unit tests with go test -json through
tools/gotestsummary. A timeout now shows the tests that were still
running and the slowest tests per package instead of a goroutine dump
that pushes the header out of the job log.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EsVtbd7MxMVsS9vP1H6KPS

.github/workflows/golang-test-linux.yml

@@ -481,14 +481,20 @@ jobs:
         if: matrix.store == 'mysql'
         run: docker pull mlsmaycon/warmed-mysql:8
 
+      # The -json stream goes through tools/gotestsummary so the log shows one
+      # line per test, the output of failed tests, the head of a timeout panic
+      # with the still-running tests, and the slowest tests per package.
       - name: Test
+        shell: bash
         run: |
+          set -o pipefail
           CGO_ENABLED=1 GOARCH=${{ matrix.arch }} \
           NETBIRD_STORE_ENGINE=${{ matrix.store }} \
             CI=true \
-          go test -tags=devcert -coverprofile=coverage.txt \
+          go test -json -tags=devcert -coverprofile=coverage.txt \
             -exec "sudo --preserve-env=CI,NETBIRD_STORE_ENGINE" \
-            -timeout 20m ./management/... ./shared/management/...
+            -timeout 20m ./management/... ./shared/management/... \
+            | go run ./tools/gotestsummary
 
       - name: Upload coverage reports to Codecov
         if: matrix.arch == 'amd64'