feat: insert the daemon context in the poller context

The daemon context is needed when the context of a job or the poller
is done. Otherwise it is no longer possible to send a conclusion
report to Forgejo, short of creating a context.Background() which
poses its own set of problems.

- WithDaemonContext is used to store the daemon context
- The poller uses the daemon context instead of context.Background

internal/pkg/common/daemon_context.go

@@ -0,0 +1,26 @@
+// Copyright 2025 The Forgejo Authors
+// SPDX-License-Identifier: MIT
+
+package common
+
+import (
+	"context"
+)
+
+type daemonContextKey string
+
+const daemonContextKeyVal = daemonContextKey("daemon")
+
+func DaemonContext(ctx context.Context) context.Context {
+	val := ctx.Value(daemonContextKeyVal)
+	if val != nil {
+		if daemon, ok := val.(context.Context); ok {
+			return daemon
+		}
+	}
+	return context.Background()
+}
+
+func WithDaemonContext(ctx, daemon context.Context) context.Context {
+	return context.WithValue(ctx, daemonContextKeyVal, daemon)
+}