feat: add Atlas Terminal — Next.js 14 + FastAPI full-stack migration

Complete migration from Streamlit to Next.js 14 App Router + FastAPI backend.

Frontend (Next.js 14):
- 10 pages: Overview, Research, Valuation, Technical, Markets, Earnings, News, Portfolio, Filings, Settings
- Terminal Noir dark theme with custom Tailwind config
- TradingView Lightweight Charts for candlestick/volume
- Valuation: DCF, Sensitivity Matrix, Monte Carlo, Tornado, Reverse DCF
- Financial Statements table with YoY growth badges and margin rows
- SEC EDGAR inline filing viewer with section tabs
- News split-view with iframe article embedding
- Technical Analysis with RSI, MACD, Bollinger, Fibonacci, Moving Averages
- Earnings beat/miss visualization
- AI Copilot chat panel with Gemini integration

Backend (FastAPI):
- 13 routers: market_data, financials, valuation, technical, earnings, insider, edgar, news, portfolio, analysis, chat, estimates, fx
- Services: DCF engine, Monte Carlo simulation, sensitivity analysis, risk metrics, SEC parser, technical indicators
- yfinance + yahooquery data sources with fallback pattern
- SQLite caching layer

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

atlas-terminal/tests/conftest.py

@@ -0,0 +1,49 @@
+"""Shared pytest fixtures for ATLAS Terminal test suite."""
+
+import sys
+from pathlib import Path
+
+import pytest
+
+# Ensure the project root is on sys.path so `server.*` imports work.
+_PROJECT_ROOT = Path(__file__).resolve().parent.parent
+if str(_PROJECT_ROOT) not in sys.path:
+    sys.path.insert(0, str(_PROJECT_ROOT))
+
+
+@pytest.fixture
+def sample_ticker():
+    """A well-known US ticker for integration-style tests."""
+    return "AAPL"
+
+
+@pytest.fixture
+def sample_fcf_inputs():
+    """Reasonable DCF inputs for unit-testing valuation functions."""
+    return {
+        "fcf": 100_000_000_000,       # $100B trailing FCF
+        "wacc": 0.10,                  # 10%
+        "terminal_growth": 0.025,      # 2.5%
+        "fcf_growth": 0.08,            # 8%
+        "total_debt": 110_000_000_000, # $110B
+        "cash": 60_000_000_000,        # $60B
+        "shares": 15_500_000_000,      # 15.5B shares
+    }
+
+
+@pytest.fixture
+def sample_balance_sheet_values():
+    """Simplified balance-sheet figures for Altman Z / DuPont tests."""
+    return {
+        "current_assets": 150_000_000_000,
+        "current_liabilities": 120_000_000_000,
+        "total_assets": 350_000_000_000,
+        "retained_earnings": 50_000_000_000,
+        "total_liabilities": 290_000_000_000,
+        "total_equity": 60_000_000_000,
+        "ebit": 120_000_000_000,
+        "sales": 400_000_000_000,
+        "market_cap": 2_800_000_000_000,
+        "net_income": 95_000_000_000,
+        "revenue": 400_000_000_000,
+    }