feat(battlecard): card 01 — market valuation extremes with CAPE trend chart

output/battlecards/cards/card_01_market_valuation.md

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+# Card 1: Market Valuation Extremes
+
+> The US stock market is trading at historic valuation extremes that mirror previous bubble periods.
+
+## Fact
+
+- The Shiller CAPE ratio stands at ~40.03, more than 2x the historical mean of 17.39 since 1881 *(Source: Yale/Shiller, 2026)*
+- The Buffett Indicator (Total Market Cap / GDP) is at 219%, well above the 200% danger threshold *(Source: FRED/World Bank composite, 2026)*
+- S&P 500 trailing P/E is at 29.6 vs historical mean of 17.9 — 65% above normal *(Source: S&P historical data, 2026)*
+- Dividend yield has fallen to 1.04%, the lowest since 1950 — offering virtually no income cushion *(Source: S&P historical data, 2026)*
+- Federal debt stands at 122.6% of GDP, adding macro fragility to the valuation overstretch *(Source: US Treasury data, 2025)*
+
+![Shiller CAPE Ratio: Current vs Historical](../charts/mini_cape_extreme.png)
+
+## Impact
+
+- **Investment risk is elevated**: Historical CAPE readings above 35 have been followed by below-average 10-year returns. Current CAPE of 40 implies negative 10-year annualized returns.
+- **AI spending amplifies the bubble**: Hyperscaler AI capex ($208B+ projected for 2026) is propping up tech stock valuations disconnected from current revenue generation.
+- **Market correction risk**: If AI ROI fails to materialize at scale, the dual pressure of overvaluation AND spending disappointment could trigger a sharp correction similar to 2000.
+
+## Act
+
+- **When debating AI market health**: Lead with valuation data. CAPE at 40+ is objectively extreme by any historical standard — only the 2000 dot-com peak (43.77) was higher in 147 years.
+- **Key question to ask**: "How much AI-driven revenue growth is priced into these valuations, and what happens if it doesn't materialize?"
+- **Counter-argument anticipation**: "This time is different because AI is transformative." Response: Dot-com stocks also traded at historic multiples before the 2000 crash. The technology (internet) proved real, but valuations were disconnected from reality.
+
+---
+
+*Last updated: June 2026 | Sources: Yale/Shiller CAPE data, FRED Buffett Indicator, S&P 500 historical metrics, US Treasury debt data*