Phase 14: add debug reinject diag logging — B-002 filter visibility

Expose settings.debug snapshots on session_compact and before_agent_start
so Phase 14 can see which filter stage drops --skill paths.

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

test/settings.test.ts

@@ -54,6 +54,10 @@ describe("parseSkillReinjectPartial", () => {
 			}),
 		).toEqual({ enabled: true, suffix: "custom" });
 	});
+
+	it("parses debug flag", () => {
+		expect(parseSkillReinjectPartial({ debug: true })).toEqual({ debug: true });
+	});
 });
 
 describe("mergeSkillReinjectSettings", () => {