Phase 14: split kept-window filter from registry gate — defer planning stage

filterSkillsNeedingReinjectByKept tracks absent skills without registeredNames; immediate path keeps the combined filter.

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

test/kept-window.test.ts

@@ -2,6 +2,7 @@ import type { SessionEntry } from "@earendil-works/pi-coding-agent";
 import { describe, expect, it } from "vitest";
 import {
 	filterSkillsNeedingReinject,
+	filterSkillsNeedingReinjectByKept,
 	getKeptEntries,
 	skillsPresentInKeptWindow,
 } from "../src/kept";
@@ -95,6 +96,23 @@ describe("skillsPresentInKeptWindow", () => {
 	});
 });
 
+describe("filterSkillsNeedingReinjectByKept", () => {
+	it("returns tracked skills absent from kept window regardless of registration", () => {
+		const keptPresent = new Set(["alpha"]);
+		expect(filterSkillsNeedingReinjectByKept(trackedSkills, keptPresent)).toEqual(["beta"]);
+	});
+
+	it("preserves tracked order including unregistered names", () => {
+		const keptPresent = new Set<string>();
+		expect(filterSkillsNeedingReinjectByKept(trackedSkills, keptPresent)).toEqual(["alpha", "beta"]);
+	});
+
+	it("returns empty when all tracked skills are in kept window", () => {
+		const keptPresent = new Set(["alpha", "beta"]);
+		expect(filterSkillsNeedingReinjectByKept(trackedSkills, keptPresent)).toEqual([]);
+	});
+});
+
 describe("filterSkillsNeedingReinject", () => {
 	it("returns registered tracked skills absent from kept window", () => {
 		const keptPresent = new Set(["alpha"]);