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.

.env.example

@@ -0,0 +1,55 @@
+# Billo Release Agent - Environment Variables
+# Copy this file to .env and fill in your values.
+# Never commit .env to source control.
+
+# ===========================================================================
+# REQUIRED
+# ===========================================================================
+
+# --- Azure DevOps ----------------------------------------------------------
+AZDO_ORGANIZATION=billodev
+AZDO_PROJECT=Billo App Platform
+AZDO_PAT=                              # Personal access token (Code read/write, Build read/execute)
+
+# --- PostgreSQL ------------------------------------------------------------
+POSTGRES_PASSWORD=                     # Used by docker-compose db service
+POSTGRES_DSN=postgresql://agent:${POSTGRES_PASSWORD}@localhost:5432/agent
+
+# --- Jira ------------------------------------------------------------------
+JIRA_EMAIL=                            # Jira account email
+JIRA_API_TOKEN=                        # Jira API token
+
+# --- Slack -----------------------------------------------------------------
+SLACK_WEBHOOK_URL=                     # Incoming webhook URL (for release notifications)
+
+# --- Webhook Security ------------------------------------------------------
+WEBHOOK_SECRET=                        # HMAC secret for Azure DevOps webhook validation
+
+# ===========================================================================
+# OPTIONAL (have defaults)
+# ===========================================================================
+
+# --- Slack App (for interactive buttons) -----------------------------------
+SLACK_BOT_TOKEN=                       # xoxb-... Bot token (needed for Slack buttons)
+SLACK_SIGNING_SECRET=                  # Slack app signing secret (needed for /slack/interactions)
+SLACK_CHANNEL_ID=                      # Channel ID to post messages (e.g., C0123456789)
+
+# --- CI/CD Polling ---------------------------------------------------------
+CI_POLL_INTERVAL_SECONDS=30            # Seconds between CI status polls
+CI_POLL_MAX_WAIT_SECONDS=1800          # Max wait for CI completion (30 min)
+
+# --- Claude Code Review ----------------------------------------------------
+# ANTHROPIC_API_KEY=                   # Not needed — uses Claude Code CLI subscription
+# CLAUDE_REVIEW_MODEL=claude-sonnet-4-20250514
+
+# --- Local Repo Path -------------------------------------------------------
+REPOS_BASE_DIR=                        # Base dir containing Billo repos (e.g., /c/Users/yaoji/git/Billo)
+
+# --- Jira ------------------------------------------------------------------
+JIRA_BASE_URL=https://billolife.atlassian.net
+
+# --- Operator API ----------------------------------------------------------
+OPERATOR_TOKEN=                        # When set, protects POST /approvals/* and POST /manual/*
+
+# --- Server ----------------------------------------------------------------
+PORT=8000