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/client-setup.md

@@ -0,0 +1,65 @@
+---
+title: Initialize Client for External Access
+impact: HIGH
+impactDescription: Enables external applications to interact with DBOS workflows
+tags: client, external, setup, initialization
+---
+
+## Initialize Client for External Access
+
+Use `dbos.NewClient` to interact with DBOS from external applications like API servers, CLI tools, or separate services. The Client connects directly to the DBOS system database.
+
+**Incorrect (using full DBOS context from an external app):**
+
+```go
+// Full DBOS context requires Launch() - too heavy for external clients
+ctx, _ := dbos.NewDBOSContext(context.Background(), config)
+dbos.Launch(ctx)
+```
+
+**Correct (using Client):**
+
+```go
+client, err := dbos.NewClient(context.Background(), dbos.ClientConfig{
+	DatabaseURL: os.Getenv("DBOS_SYSTEM_DATABASE_URL"),
+})
+if err != nil {
+	log.Fatal(err)
+}
+defer client.Shutdown(10 * time.Second)
+
+// Send a message to a workflow
+err = client.Send(workflowID, "notification", "topic")
+
+// Get an event from a workflow
+event, err := client.GetEvent(workflowID, "status", 60*time.Second)
+
+// Retrieve a workflow handle
+handle, err := client.RetrieveWorkflow(workflowID)
+result, err := handle.GetResult()
+
+// List workflows
+workflows, err := client.ListWorkflows(
+	dbos.WithStatus([]dbos.WorkflowStatusType{dbos.WorkflowStatusError}),
+)
+
+// Workflow management
+err = client.CancelWorkflow(workflowID)
+handle, err = client.ResumeWorkflow(workflowID)
+
+// Read a stream
+values, closed, err := client.ClientReadStream(workflowID, "results")
+
+// Read a stream asynchronously
+ch, err := client.ClientReadStreamAsync(workflowID, "results")
+```
+
+ClientConfig options:
+- `DatabaseURL` (required unless `SystemDBPool` is set): PostgreSQL connection string
+- `SystemDBPool`: Custom `*pgxpool.Pool`
+- `DatabaseSchema`: Schema name (default: `"dbos"`)
+- `Logger`: Custom `*slog.Logger`
+
+Always call `client.Shutdown()` when done.
+
+Reference: [DBOS Client](https://docs.dbos.dev/golang/reference/client)