Add the default Structured Liquidity KPI grid

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Summary

• add reusable KpiGrid and KpiCard shadcn registry components
• standardize square metric cards, comparison badges, tooltips, responsive layout, and loading/unavailable states
• register the KPI surface as a stable default pattern and document the contract for adopters
• explicitly require applications to supply audited values rather than component-level fallback metrics

Validation

• registry generation and schema consistency: passed (82 items)
• adopter registry: passed (9 projects)
• Structured Liquidity artifact typecheck: passed
• Structured Liquidity production build: passed
• full workspace typecheck could not resolve unrelated workspace dependencies from the isolated worktree; the same primary checkout baseline passed before this feature work