Merge pull request #22 from olujimiAdebakin/feature/AFPU_MODEL

Executive Summary
This PR fundamentally redesigns the funding rate mechanism by implementing the Accumulated Funding Per Unit (AFPU) model. This architectural change eliminates per-trader iteration, reducing gas costs from O(n) to O(1) and enabling the protocol to scale from hundreds to millions of active positions.
Key Metrics:

Gas Reduction: 99% reduction at scale (from ~10M to ~50K gas for 1,000 traders)
Scalability: Removes theoretical limit on concurrent positions
Precision: Maintains per-second funding accuracy
Standard: Adopts battle-tested model used by dYdX, GMX, and other leading protocols

Author: olujimiAdebakin

.gitattributes

@@ -0,0 +1,10 @@
+# Language overrides
+*.sol linguist-language=Solidity
+*.js linguist-language=JavaScript
+*.ts linguist-language=TypeScript
+*.md linguist-language=Markdown
+
+# Ignore vendor/third-party code from detection
+vendor/** linguist-vendored
+node_modules/** linguist-vendored
+test/** linguist-documentation