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/services/test_pr_dedup.py

@@ -0,0 +1,141 @@
+"""Tests for services/pr_dedup.py. Written FIRST (TDD RED phase).
+
+find_unprocessed_prs queries agent_threads to find which PRs have not yet
+been processed (no existing thread for that repo+pr_id combination).
+"""
+
+import pytest
+
+from release_agent.models.pr import PRInfo
+from release_agent.services.pr_dedup import find_unprocessed_prs
+
+
+# ---------------------------------------------------------------------------
+# Helpers — fake async pool
+# ---------------------------------------------------------------------------
+
+def _make_pr(pr_id: str, repo_name: str = "my-repo") -> PRInfo:
+    return PRInfo(
+        pr_id=pr_id,
+        pr_url=f"https://dev.azure.com/org/proj/_git/{repo_name}/pullrequest/{pr_id}",
+        repo_name=repo_name,
+        branch="refs/heads/feature/ALLPOST-100-fix",
+        pr_title=f"PR {pr_id}",
+        pr_status="active",
+    )
+
+
+def _make_pool(existing_rows: list[tuple[str, str]]):
+    """Return a fake async connection pool.
+
+    existing_rows: list of (pr_id, repo_name) tuples representing already-processed PRs.
+    """
+
+    class FakeCursor:
+        def __init__(self, rows):
+            self._rows = rows
+
+        async def execute(self, sql, params=None):
+            pass
+
+        async def fetchall(self):
+            return self._rows
+
+        async def __aenter__(self):
+            return self
+
+        async def __aexit__(self, *args):
+            pass
+
+    class FakeConn:
+        def __init__(self, rows):
+            self._rows = rows
+
+        def cursor(self):
+            return FakeCursor(self._rows)
+
+        async def __aenter__(self):
+            return self
+
+        async def __aexit__(self, *args):
+            pass
+
+    class FakePool:
+        def __init__(self, rows):
+            self._rows = rows
+
+        def connection(self):
+            return FakeConn(self._rows)
+
+    return FakePool(existing_rows)
+
+
+# ---------------------------------------------------------------------------
+# find_unprocessed_prs tests
+# ---------------------------------------------------------------------------
+
+class TestFindUnprocessedPrs:
+
+    async def test_returns_all_when_none_processed(self) -> None:
+        prs = [_make_pr("10"), _make_pr("20")]
+        pool = _make_pool([])
+
+        result = await find_unprocessed_prs(pool, prs)
+
+        assert len(result) == 2
+
+    async def test_returns_empty_when_all_processed(self) -> None:
+        prs = [_make_pr("10"), _make_pr("20")]
+        # existing rows: (pr_id, repo_name)
+        pool = _make_pool([("10", "my-repo"), ("20", "my-repo")])
+
+        result = await find_unprocessed_prs(pool, prs)
+
+        assert result == []
+
+    async def test_returns_only_unprocessed(self) -> None:
+        prs = [_make_pr("10"), _make_pr("20"), _make_pr("30")]
+        pool = _make_pool([("10", "my-repo")])
+
+        result = await find_unprocessed_prs(pool, prs)
+
+        pr_ids = [p.pr_id for p in result]
+        assert "10" not in pr_ids
+        assert "20" in pr_ids
+        assert "30" in pr_ids
+
+    async def test_empty_input_returns_empty(self) -> None:
+        pool = _make_pool([])
+
+        result = await find_unprocessed_prs(pool, [])
+
+        assert result == []
+
+    async def test_different_repos_not_confused(self) -> None:
+        pr_repo_a = _make_pr("10", repo_name="repo-a")
+        pr_repo_b = _make_pr("10", repo_name="repo-b")
+        # Only repo-a/10 is processed
+        pool = _make_pool([("10", "repo-a")])
+
+        result = await find_unprocessed_prs(pool, [pr_repo_a, pr_repo_b])
+
+        # repo-b/10 should still be returned (different repo)
+        assert len(result) == 1
+        assert result[0].repo_name == "repo-b"
+
+    async def test_returns_list_of_pr_info(self) -> None:
+        prs = [_make_pr("42")]
+        pool = _make_pool([])
+
+        result = await find_unprocessed_prs(pool, prs)
+
+        assert all(isinstance(p, PRInfo) for p in result)
+
+    async def test_preserves_pr_info_objects(self) -> None:
+        pr = _make_pr("77")
+        pool = _make_pool([])
+
+        result = await find_unprocessed_prs(pool, [pr])
+
+        assert result[0].pr_id == "77"
+        assert result[0].repo_name == "my-repo"