feat(coding-agent): implemented ordered compaction fallback and settings

- Replaced legacy `compaction.strategy` and `remoteEnabled` settings with `compaction.methodOrder` across session maintenance, schema, and tests.
- Added automatic fallback mechanism to try subsequent compaction methods upon failure or unsupported model capabilities.
- Added mouse drag-and-drop reordering support and click handlers to multi-select settings submenus.
- Updated documentation and test suites to reflect ordered compaction strategy preferences and fallback chains.

packages/coding-agent/test/agent-session-auto-compaction-progress-guard.test.ts

@@ -859,7 +859,7 @@ describe("AgentSession auto-compaction progress guard", () => {
 	});
 
 	it("does not restore a length stop after handoff recovery commits", async () => {
-		session.settings.set("compaction.strategy", "handoff");
+		session.settings.set("compaction.methodOrder", ["handoff", "soft"]);
 		session.settings.set("contextPromotion.enabled", false);
 		const promptSpy = vi.spyOn(session.agent, "prompt").mockResolvedValue(undefined as never);
 		const continueSpy = vi.spyOn(session.agent, "continue").mockResolvedValue();
@@ -1163,7 +1163,7 @@ describe("AgentSession auto-compaction progress guard", () => {
 		// Pin the threshold so the recovery band is exact: floor(76384 * 0.8) = 61107.
 		session.settings.set("compaction.thresholdTokens", 76384);
 		session.settings.set("compaction.thresholdPercent", -1);
-		session.settings.set("compaction.strategy", "context-full");
+		session.settings.set("compaction.methodOrder", ["soft"]);
 		session.settings.set("compaction.dropUseless", true);
 		session.settings.set("compaction.supersedeReads", true);
 		session.settings.set("compaction.keepRecentTokens", 10000);