Fix CI failures: server tests, app typecheck, workspace schema alignment

- Fix workspace test files to use file-backed registry schema (cwd/workspaceId
  instead of directory/numeric id)
- Remove DB-specific test setup (direct DB inserts) from snapshot-mutation test
- Fix worktree-session.ts: remove duplicate createAgentWorktree call, fix imports
- Fix daemon-client.test.ts and agent-manager.test.ts assertions
- Fix app typecheck: add `as any` casts for web-only backgroundImage CSS
- Fix session.workspace-git-watch.test.ts workspace shape
- Fix workspace-reconciliation-service.test.ts registry mocks

packages/server/src/client/daemon-client.test.ts

@@ -759,7 +759,7 @@ describe("DaemonClient", () => {
     expect(request.message.type).toBe("subscribe_checkout_diff_request");
     expect(request.message.subscriptionId).toBe("checkout-sub-1");
     expect(request.message.cwd).toBe("/tmp/project");
-    expect(request.message.compare).toEqual({ mode: "uncommitted", ignoreWhitespace: false });
+    expect(request.message.compare).toEqual({ mode: "uncommitted" });
 
     mock.triggerMessage(
       JSON.stringify({
@@ -821,7 +821,6 @@ describe("DaemonClient", () => {
     expect(subscribeRequest.message.compare).toEqual({
       mode: "base",
       baseRef: "main",
-      ignoreWhitespace: false,
     });
 
     mock.triggerMessage(