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/client-setup.md

@@ -0,0 +1,57 @@
+---
+title: Initialize DBOSClient for External Access
+impact: HIGH
+impactDescription: Enables external applications to interact with DBOS
+tags: client, setup, initialization, external
+---
+
+## Initialize DBOSClient for External Access
+
+Use `DBOSClient` to interact with DBOS from external applications (API servers, CLI tools, etc.).
+
+**Incorrect (no cleanup):**
+
+```python
+from dbos import DBOSClient
+
+client = DBOSClient(system_database_url=db_url)
+handle = client.enqueue(options, data)
+# Connection leaked - no destroy()!
+```
+
+**Correct (with cleanup):**
+
+```python
+import os
+from dbos import DBOSClient
+
+client = DBOSClient(
+    system_database_url=os.environ["DBOS_SYSTEM_DATABASE_URL"]
+)
+
+try:
+    handle = client.enqueue(options, data)
+    result = handle.get_result()
+finally:
+    client.destroy()
+```
+
+Constructor parameters:
+- `system_database_url`: Connection string to DBOS system database
+- `serializer`: Must match the DBOS application's serializer (default: pickle)
+
+## API Reference
+
+Beyond `enqueue`, DBOSClient mirrors the DBOS API. Use the same patterns from other reference files:
+
+| DBOSClient method | Same as DBOS method |
+|-------------------|---------------------|
+| `client.send()` | `DBOS.send()` - add `idempotency_key` for exactly-once |
+| `client.get_event()` | `DBOS.get_event()` |
+| `client.read_stream()` | `DBOS.read_stream()` |
+| `client.list_workflows()` | `DBOS.list_workflows()` |
+| `client.cancel_workflow()` | `DBOS.cancel_workflow()` |
+| `client.resume_workflow()` | `DBOS.resume_workflow()` |
+| `client.retrieve_workflow()` | `DBOS.retrieve_workflow()` |
+
+Reference: [DBOSClient](https://docs.dbos.dev/python/reference/client)