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-python/references/workflow-background.md

@@ -0,0 +1,58 @@
+---
+title: Start Workflows in Background
+impact: CRITICAL
+impactDescription: Background workflows survive crashes and restarts
+tags: workflow, background, start_workflow, handle
+---
+
+## Start Workflows in Background
+
+Use `DBOS.start_workflow` to run workflows in the background. This returns a handle to monitor or retrieve results.
+
+**Incorrect (using threads):**
+
+```python
+import threading
+
+@DBOS.workflow()
+def long_task(data):
+    # Long running work
+    pass
+
+# Don't use threads for DBOS workflows!
+thread = threading.Thread(target=long_task, args=(data,))
+thread.start()
+```
+
+**Correct (using start_workflow):**
+
+```python
+from dbos import DBOS, WorkflowHandle
+
+@DBOS.workflow()
+def long_task(data):
+    # Long running work
+    return "done"
+
+# Start workflow in background
+handle: WorkflowHandle = DBOS.start_workflow(long_task, data)
+
+# Later, get the result
+result = handle.get_result()
+
+# Or check status
+status = handle.get_status()
+```
+
+You can retrieve a workflow handle later using its ID:
+
+```python
+# Get workflow ID
+workflow_id = handle.get_workflow_id()
+
+# Later, retrieve the handle
+handle = DBOS.retrieve_workflow(workflow_id)
+result = handle.get_result()
+```
+
+Reference: [Starting Workflows](https://docs.dbos.dev/python/tutorials/workflow-tutorial#starting-workflows-in-the-background)