feat(crashtracker): add orchestrion auto-injection aspect

Add an orchestrion aspect that prepends crashtracker.Start() as the first
statement of every program's main() function at compile time, enabling
transparent crash report capture without any source changes.

The aspect uses prepend-statements (not inject-declarations/func init())
because SetCrashOutput must run inside main(), after all package init()s
have completed but before any user code executes. This matches the RFC's
requirement for the monitor process to be established before any goroutine
can crash.

Env-gating (DD_CRASHTRACKING_ENABLED, default true) is handled inside
Start() itself, so the injected statement is a single unconditional call.

Regenerates orchestrion/all/orchestrion.tool.go to include the crashtracker
package. Adds a harness integration test confirming the aspect wires correctly
under orchestrion's compile-time transformation.

Author: kakkoyun

crashtracker/orchestrion.yml

@@ -0,0 +1,28 @@
+# Unless explicitly stated otherwise all files in this repository are licensed
+# under the Apache License Version 2.0.
+# This product includes software developed at Datadog (https://www.datadoghq.com/).
+# Copyright 2016-present Datadog, Inc.
+---
+# yaml-language-server: $schema=https://datadoghq.dev/orchestrion/schema.json
+meta:
+  name: github.com/DataDog/dd-trace-go/v2/crashtracker
+  description: |-
+    Starts the Datadog crashtracker as the first statement of main(), so the
+    monitor process is established before any goroutine can crash.
+
+aspects:
+  - id: func main()
+    join-point:
+      all-of:
+        - package-name: main
+        - test-main: false
+        - function-body:
+            function:
+              - name: main
+              - signature: {}
+    advice:
+      - prepend-statements:
+          imports:
+            crashtracker: github.com/DataDog/dd-trace-go/v2/crashtracker
+          template: |-
+            crashtracker.Start()

internal/orchestrion/_integration/crashtracker/crashtracker.go

@@ -0,0 +1,27 @@
+// Unless explicitly stated otherwise all files in this repository are licensed
+// under the Apache License Version 2.0.
+// This product includes software developed at Datadog (https://www.datadoghq.com/).
+// Copyright 2016-present Datadog, Inc.
+
+package crashtracker
+
+import (
+	"context"
+	"testing"
+
+	"github.com/DataDog/dd-trace-go/v2/internal/orchestrion/_integration/internal/trace"
+)
+
+// TestCase verifies that crashtracker.Start() is injected into main() by
+// orchestrion. The crashtracker does not produce trace spans, so the test
+// only validates that the instrumented binary runs without crashing due to
+// a missing Start() call.
+type TestCase struct{}
+
+func (*TestCase) Setup(_ context.Context, _ *testing.T) {}
+
+func (*TestCase) Run(_ context.Context, _ *testing.T) {}
+
+func (*TestCase) ExpectedTraces() trace.Traces {
+	return trace.Traces{}
+}