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/step-retries.md

@@ -0,0 +1,66 @@
+---
+title: Configure Step Retries for Transient Failures
+impact: HIGH
+impactDescription: Automatic retries handle transient failures without manual code
+tags: step, retry, exponential-backoff, resilience
+---
+
+## Configure Step Retries for Transient Failures
+
+Steps can automatically retry on failure with exponential backoff. This handles transient failures like network issues.
+
+**Incorrect (manual retry logic):**
+
+```go
+func fetchData(ctx context.Context) (string, error) {
+	var lastErr error
+	for attempt := 0; attempt < 3; attempt++ {
+		resp, err := http.Get("https://api.example.com")
+		if err == nil {
+			defer resp.Body.Close()
+			body, _ := io.ReadAll(resp.Body)
+			return string(body), nil
+		}
+		lastErr = err
+		time.Sleep(time.Duration(math.Pow(2, float64(attempt))) * time.Second)
+	}
+	return "", lastErr
+}
+```
+
+**Correct (built-in retries with `dbos.RunAsStep`):**
+
+```go
+func fetchData(ctx context.Context) (string, error) {
+	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"),
+		dbos.WithStepMaxRetries(10),
+		dbos.WithBaseInterval(500*time.Millisecond),
+		dbos.WithBackoffFactor(2.0),
+		dbos.WithMaxInterval(5*time.Second),
+	)
+	return data, err
+}
+```
+
+Retry parameters:
+- `WithStepMaxRetries(n)`: Maximum retry attempts (default: `0` — no retries)
+- `WithBaseInterval(d)`: Initial delay between retries (default: `100ms`)
+- `WithBackoffFactor(f)`: Multiplier for exponential backoff (default: `2.0`)
+- `WithMaxInterval(d)`: Maximum delay between retries (default: `5s`)
+
+With defaults, retry delays are: 100ms, 200ms, 400ms, 800ms, 1.6s, 3.2s, 5s, 5s...
+
+If all retries are exhausted, a `DBOSError` with code `MaxStepRetriesExceeded` is returned to the calling workflow.
+
+Reference: [Configurable Retries](https://docs.dbos.dev/golang/tutorials/step-tutorial#configurable-retries)