feat(ci): Add automated performance tracing to CI pipeline (#12)

* feat(ci): Add automated performance tracing to CI pipeline

Integrates dotnet-trace into the CI workflow to automatically generate
performance flamegraphs using HelloWorldBot as the test application.
This enables continuous performance monitoring and helps identify
regressions early in the development cycle.

The performance-trace job:
- Builds and runs HelloWorldBot
- Collects 30-second performance trace using dotnet-trace
- Converts to Speedscope format for visualization
- Uploads flamegraph as workflow artifact (7-day retention)
- Added as required check in all-tests-passed job

Author: neil-pozetroninc

.github/workflows/dotnet.yml

@@ -91,10 +91,75 @@ jobs:
           retention-days: 7
           if-no-files-found: ignore
 
+  performance-trace:
+    name: Performance Trace
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Setup .NET
+        uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: 8.0.x
+      - name: Install dotnet-trace
+        run: dotnet tool install --global dotnet-trace
+      - name: Restore Dependencies
+        run: dotnet restore ProbotSharp.sln
+      - name: Restore HelloWorldBot
+        run: dotnet restore examples/HelloWorldBot/HelloWorldBot.csproj
+      - name: Build HelloWorldBot
+        run: dotnet build examples/HelloWorldBot/HelloWorldBot.csproj -c Release --no-restore
+      - name: Create dummy GitHub App private key
+        run: |
+          cat > /tmp/trace-dummy-key.pem <<'EOF'
+          -----BEGIN RSA PRIVATE KEY-----
+          MIIEowIBAAKCAQEA0Z6Wh6dULwk3p0c2EhjRz1EOwN+R0EQJfzH3AwiBvT7nPzUG
+          ----END RSA PRIVATE KEY-----
+          EOF
+      - name: Run HelloWorldBot in background
+        env:
+          PROBOTSHARP__GITHUB__APPID: "123456"
+          PROBOTSHARP__WEBHOOK_SECRET: "test-secret-for-tracing"
+          PROBOTSHARP__GITHUB__PRIVATEKEYPATH: "/tmp/trace-dummy-key.pem"
+          TMPDIR: /tmp
+          DOTNET_DiagnosticPorts: ""
+        run: |
+          dotnet run --project examples/HelloWorldBot/HelloWorldBot.csproj -c Release > /tmp/app.log 2>&1 &
+          echo $! > app.pid
+          echo "Started HelloWorldBot with PID $(cat app.pid)"
+      - name: Wait for app to initialize
+        run: sleep 15
+      - name: Check if process is running
+        run: |
+          PID=$(cat app.pid)
+          echo "Checking if PID $PID is running..."
+          ps -p $PID || (echo "Process not running!" && cat /tmp/app.log && exit 1)
+          echo "Process is alive and running"
+          echo "--- Checking dotnet-trace can see the process ---"
+          dotnet-trace ps || true
+          echo "--- Listing diagnostic sockets in /tmp ---"
+          ls -la /tmp/dotnet-diagnostic-* || echo "No diagnostic sockets found"
+          echo "--- App output so far ---"
+          cat /tmp/app.log
+      - name: Collect performance trace
+        env:
+          TMPDIR: /tmp
+        run: |
+          echo "Collecting trace from HelloWorldBot process..."
+          echo "TMPDIR is set to: $TMPDIR"
+          dotnet-trace collect --name HelloWorldBot --providers Microsoft-Windows-DotNETRuntime --duration 00:00:30 -o trace.nettrace || (echo "Trace collection failed!" && exit 1)
+      - name: Convert trace to Speedscope format
+        run: dotnet-trace convert trace.nettrace --format Speedscope
+      - name: Upload flamegraph artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: flamegraph
+          path: trace.speedscope.json
+          retention-days: 7
+
   all-tests-passed:
     name: All Tests Passed
     runs-on: ubuntu-latest
-    needs: [build-test, verify-links, verify-markdown-code, test-examples]
+    needs: [build-test, verify-links, verify-markdown-code, test-examples, performance-trace]
     steps:
       - run: echo "✅ All tests passed successfully!"