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-constraints.md

@@ -0,0 +1,68 @@
+---
+title: Follow Workflow Constraints
+impact: CRITICAL
+impactDescription: Violating constraints breaks recovery and durability guarantees
+tags: workflow, constraints, rules, best-practices
+---
+
+## Follow Workflow Constraints
+
+Workflows have specific constraints to maintain durability guarantees. Violating them can break recovery.
+
+**Incorrect (starting workflows from steps):**
+
+```go
+func myStep(ctx context.Context) (string, error) {
+	// Don't start workflows from steps!
+	// The step's context.Context does not support workflow operations
+	return "", nil
+}
+
+func myWorkflow(ctx dbos.DBOSContext, input string) (string, error) {
+	// Starting a child workflow inside a step breaks determinism
+	dbos.RunAsStep(ctx, func(ctx context.Context) (string, error) {
+		handle, _ := dbos.RunWorkflow(ctx.(dbos.DBOSContext), otherWorkflow, "data") // WRONG
+		return handle.GetWorkflowID(), nil
+	})
+	return "", nil
+}
+```
+
+**Correct (workflow operations only from workflows):**
+
+```go
+func fetchData(ctx context.Context) (string, error) {
+	// Steps only do external operations
+	resp, err := http.Get("https://api.example.com")
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+	body, _ := io.ReadAll(resp.Body)
+	return string(body), nil
+}
+
+func myWorkflow(ctx dbos.DBOSContext, input string) (string, error) {
+	data, err := dbos.RunAsStep(ctx, fetchData, dbos.WithStepName("fetchData"))
+	if err != nil {
+		return "", err
+	}
+	// Start child workflows from the parent workflow
+	handle, err := dbos.RunWorkflow(ctx, otherWorkflow, data)
+	if err != nil {
+		return "", err
+	}
+	// Receive messages from the workflow
+	msg, err := dbos.Recv[string](ctx, "topic", 60*time.Second)
+	// Set events from the workflow
+	dbos.SetEvent(ctx, "status", "done")
+	return data, nil
+}
+```
+
+Additional constraints:
+- Don't modify global variables from workflows or steps
+- All workflows and queues must be registered **before** `Launch()`
+- Concurrent steps must start in deterministic order using `dbos.Go`/`dbos.Select`
+
+Reference: [Workflow Guarantees](https://docs.dbos.dev/golang/tutorials/workflow-tutorial#workflow-guarantees)