Add $ prefix to cost in footer

Fixes #53

packages/coding-agent/CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## [Unreleased]
+
+### Fixed
+
+- **Footer Cost Display**: Added `$` prefix to cost display in footer. Now shows `$0.078` instead of `0.078`. ([#53](https://github.com/badlogic/pi-mono/issues/53))
+
 ## [0.9.3] - 2025-11-24
 
 ### Added

packages/coding-agent/src/tui/footer.ts

@@ -85,7 +85,7 @@ export class FooterComponent implements Component {
 		if (totalOutput) statsParts.push(`↓${formatTokens(totalOutput)}`);
 		if (totalCacheRead) statsParts.push(`R${formatTokens(totalCacheRead)}`);
 		if (totalCacheWrite) statsParts.push(`W${formatTokens(totalCacheWrite)}`);
-		if (totalCost) statsParts.push(`${totalCost.toFixed(3)}`);
+		if (totalCost) statsParts.push(`$${totalCost.toFixed(3)}`);
 
 		// Colorize context percentage based on usage
 		let contextPercentStr: string;