feat: initial commit — Billo Release Agent (LangGraph)

LangGraph-based release automation agent with:
- PR discovery (webhook + polling)
- AI code review via Claude Code CLI (subscription-based)
- Auto-create Jira tickets for PRs without ticket ID
- Jira ticket lifecycle management (code review -> staging -> done)
- CI/CD pipeline trigger, polling, and approval gates
- Slack interactive messages with approval buttons
- Per-repo semantic versioning
- PostgreSQL persistence (threads, staging, releases)
- FastAPI API (webhooks, approvals, status, manual triggers)
- Docker Compose deployment

1069 tests, 95%+ coverage.

tests/tools/fixtures/azdo_pipelines.json

@@ -0,0 +1,15 @@
+{
+  "value": [
+    {
+      "id": 10,
+      "name": "Release Pipeline",
+      "folder": "\\"
+    },
+    {
+      "id": 20,
+      "name": "Build Pipeline",
+      "folder": "\\"
+    }
+  ],
+  "count": 2
+}