refactor(omo-codex): rename ultragoal component to ulw-loop

Fully rename the ultragoal component to ulw-loop so the identifier
matches the ulw-loop skill it powers. Renames the component directory,
nested skill, TS identifiers (UlwLoop / ULW_LOOP_* / ulwLoop*), the
omo ulw-loop CLI subcommand, the .omo/ulw-loop state directory, the
OMO_ULW_LOOP_STEER directive token, and the @code-yeongyu/codex-ulw-loop
package. Also threads Atlas-style right-sized parallel worker delegation
and a Prometheus-style QA + maximum-parallelism plan into the ulw-loop
skill, with a critical post-subagent QA gate.

Updates aggregate wiring (plugin package components, hooks.json,
sync-skills), the install-codex agent-link test fixture, and user docs.

packages/omo-codex/plugin/components/ulw-loop/test/paths.test.ts

@@ -0,0 +1,31 @@
+import { describe, expect, it } from "vitest";
+
+import { repoRelative, ulwLoopBriefPath, ulwLoopDir, ulwLoopGoalsPath, ulwLoopLedgerPath } from "../src/paths.ts";
+
+describe("ulwLoopDir(repo)", () => {
+	it("returns repo + '/.omo/ulw-loop'", () => {
+		// when/then
+		expect(ulwLoopDir("/repo")).toBe("/repo/.omo/ulw-loop");
+	});
+});
+
+describe("ulw-loop*Path helpers", () => {
+	it("compose artifact filenames under ulwLoopDir", () => {
+		// when/then
+		expect(ulwLoopBriefPath("/r")).toBe("/r/.omo/ulw-loop/brief.md");
+		expect(ulwLoopGoalsPath("/r")).toBe("/r/.omo/ulw-loop/goals.json");
+		expect(ulwLoopLedgerPath("/r")).toBe("/r/.omo/ulw-loop/ledger.jsonl");
+	});
+});
+
+describe("repoRelative", () => {
+	it("strips repo prefix when path is inside repo", () => {
+		// when/then
+		expect(repoRelative("/repo/.omo/ulw-loop/goals.json", "/repo")).toBe(".omo/ulw-loop/goals.json");
+	});
+
+	it("returns absolute when path is outside repo", () => {
+		// when/then
+		expect(repoRelative("/elsewhere/file", "/repo")).toBe("/elsewhere/file");
+	});
+});