feat: add DBOS skills for TypeScript, Python, and Go (#94)

Add three DBOS SDK skills with reference documentation for building
reliable, fault-tolerant applications with durable workflows.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

skills/dbos-golang/references/workflow-background.md

@@ -0,0 +1,64 @@
+---
+title: Start Workflows in Background
+impact: CRITICAL
+impactDescription: Background workflows enable reliable async processing
+tags: workflow, background, handle, async
+---
+
+## Start Workflows in Background
+
+Use `dbos.RunWorkflow` to start a workflow and get a handle to track it. The workflow is guaranteed to run to completion even if the app is interrupted.
+
+**Incorrect (no way to track background work):**
+
+```go
+func processData(ctx dbos.DBOSContext, data string) (string, error) {
+	// ...
+	return "processed: " + data, nil
+}
+
+// Fire and forget in a goroutine - no durability, no tracking
+go func() {
+	processData(ctx, data)
+}()
+```
+
+**Correct (using RunWorkflow):**
+
+```go
+func processData(ctx dbos.DBOSContext, data string) (string, error) {
+	return "processed: " + data, nil
+}
+
+func main() {
+	// ... setup and launch ...
+
+	// Start workflow, get handle
+	handle, err := dbos.RunWorkflow(ctx, processData, "input")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Get the workflow ID
+	fmt.Println(handle.GetWorkflowID())
+
+	// Wait for result
+	result, err := handle.GetResult()
+
+	// Check status
+	status, err := handle.GetStatus()
+}
+```
+
+Retrieve a handle later by workflow ID:
+
+```go
+handle, err := dbos.RetrieveWorkflow[string](ctx, workflowID)
+result, err := handle.GetResult()
+```
+
+`GetResult` supports options:
+- `dbos.WithHandleTimeout(timeout)`: Return a timeout error if the workflow doesn't complete within the duration
+- `dbos.WithHandlePollingInterval(interval)`: Control how often the database is polled for completion
+
+Reference: [Workflows](https://docs.dbos.dev/golang/tutorials/workflow-tutorial)