feat(sproutclaw): modularize webui, extensions, and agent config layout

Restructure local extensions into per-feature directories, split WebUI
into backend modules with slash commands and systemd support, and track
prompts/skills under .pi/agent for portable Gitea deployment.

Co-authored-by: Cursor <cursoragent@cursor.com>

packages/coding-agent/test/skills.test.ts

@@ -105,6 +105,17 @@ describe("skills", () => {
 			expect(diagnostics).toHaveLength(0);
 		});
 
+		it("should ignore README.md at the skills directory root", () => {
+			const { skills, diagnostics } = loadSkillsFromDir({
+				dir: join(fixturesDir, "skills-dir-readme"),
+				source: "test",
+			});
+
+			expect(skills).toHaveLength(1);
+			expect(skills[0].name).toBe("nested-skill");
+			expect(diagnostics).toHaveLength(0);
+		});
+
 		it("should prefer a directory's root SKILL.md over nested SKILL.md files", () => {
 			const { skills, diagnostics } = loadSkillsFromDir({
 				dir: join(fixturesDir, "root-skill-preferred"),