feat: CONAI Phase 1 MVP 초기 구현

소형 건설업체(100억 미만)를 위한 AI 기반 토목공사 통합관리 플랫폼

Backend (FastAPI):
- SQLAlchemy 모델 13개 (users, projects, wbs, tasks, daily_reports, reports, inspections, quality, weather, permits, rag, settings)
- API 라우터 11개 (auth, projects, tasks, daily_reports, reports, inspections, weather, rag, kakao, permits, settings)
- Services: Claude AI 래퍼, CPM Gantt 계산, 기상청 API, RAG(pgvector), 카카오 Skill API
- Alembic 마이그레이션 (pgvector 포함)
- pytest 테스트 (CPM, 날씨 경보)

Frontend (Next.js 15):
- 11개 페이지 (대시보드, 프로젝트, Gantt, 일보, 검측, 품질, 날씨, 인허가, RAG, 설정)
- TanStack Query + Zustand + Tailwind CSS

인프라:
- Docker Compose (PostgreSQL pgvector + backend + frontend)
- 한국어 README 및 설치 가이드

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/tests/test_gantt.py

@@ -0,0 +1,76 @@
+"""Tests for CPM Gantt calculation."""
+import pytest
+from datetime import date
+from unittest.mock import MagicMock
+import uuid
+from app.services.gantt import compute_cpm
+
+
+def make_task(name: str, start: str, end: str) -> MagicMock:
+    t = MagicMock()
+    t.id = uuid.uuid4()
+    t.name = name
+    t.planned_start = date.fromisoformat(start)
+    t.planned_end = date.fromisoformat(end)
+    return t
+
+
+def make_dep(pred_id, succ_id) -> MagicMock:
+    d = MagicMock()
+    d.predecessor_id = pred_id
+    d.successor_id = succ_id
+    return d
+
+
+def test_cpm_no_dependencies():
+    tasks = [
+        make_task("A", "2026-04-01", "2026-04-05"),
+        make_task("B", "2026-04-01", "2026-04-10"),
+    ]
+    result = compute_cpm(tasks, [])
+    assert isinstance(result, tuple)
+    cpm_data, duration = result
+    assert len(cpm_data) == 2
+    assert duration > 0
+
+
+def test_cpm_serial_tasks():
+    t1 = make_task("A", "2026-04-01", "2026-04-05")
+    t2 = make_task("B", "2026-04-06", "2026-04-10")
+    dep = make_dep(t1.id, t2.id)
+
+    result = compute_cpm([t1, t2], [dep])
+    assert isinstance(result, tuple)
+    cpm_data, duration = result
+
+    # Serial tasks: both should be critical
+    assert cpm_data[t1.id]["is_critical"] is True
+    assert cpm_data[t2.id]["is_critical"] is True
+
+
+def test_cpm_parallel_tasks():
+    """In parallel paths, only the longer path is critical."""
+    t_start = make_task("Start", "2026-04-01", "2026-04-02")
+    t_long = make_task("Long Path", "2026-04-03", "2026-04-20")  # 18 days
+    t_short = make_task("Short Path", "2026-04-03", "2026-04-10")  # 8 days
+    t_end = make_task("End", "2026-04-21", "2026-04-22")
+
+    deps = [
+        make_dep(t_start.id, t_long.id),
+        make_dep(t_start.id, t_short.id),
+        make_dep(t_long.id, t_end.id),
+        make_dep(t_short.id, t_end.id),
+    ]
+
+    result = compute_cpm([t_start, t_long, t_short, t_end], deps)
+    assert isinstance(result, tuple)
+    cpm_data, duration = result
+
+    # Long path and start/end should be critical; short path should not
+    assert cpm_data[t_long.id]["is_critical"] is True
+    assert cpm_data[t_short.id]["is_critical"] is False
+
+
+def test_cpm_empty_tasks():
+    result = compute_cpm([], [])
+    assert result == {}