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>

.gitignore

@@ -20,5 +20,32 @@ build/
 # IDE
 .idea/
 .vscode/
+.cursor/
 *.swp
 *.swo
+
+# Node / Next.js
+node_modules/
+.next/
+.turbo/
+
+# SQLite
+*.db
+*.db-shm
+*.db-wal
+
+# Claude
+.claude/
+
+# Package locks (keep only package.json)
+package-lock.json
+
+# SEC EDGAR cache
+SEC-EDGAR-Filings/
+
+# Backup directories
+*-backup/
+
+# Prompt files
+CLAUDE_CODE_PROMPT.md
+REFACTORING_PROMPT.md