Add skills system with Claude Code compatibility (#171)

* Add skills system with Claude Code compatibility

* consolidate skills into single module, merge loaders, add <available_skills> XML tags

* add Codex CLI skills compatibility, skip hidden/symlinks

packages/coding-agent/src/main.ts

@@ -241,7 +241,13 @@ export async function main(args: string[]) {
 	}
 
 	// Build system prompt
-	const systemPrompt = buildSystemPrompt(parsed.systemPrompt, parsed.tools, parsed.appendSystemPrompt);
+	const skillsEnabled = !parsed.noSkills && settingsManager.getSkillsEnabled();
+	const systemPrompt = buildSystemPrompt({
+		customPrompt: parsed.systemPrompt,
+		selectedTools: parsed.tools,
+		appendSystemPrompt: parsed.appendSystemPrompt,
+		skillsEnabled,
+	});
 
 	// Handle session restoration
 	let modelFallbackMessage: string | null = null;