feat: 1Password Connect secret sources for SSH credentials (#1341)

* feat: 1Password Connect secret sources for SSH credentials

Hosts and credentials can hold op://vault/item/field references instead
of secrets; they are resolved at connect time from the user's secret
source (1Password Connect) at the single point where every subsystem
receives plaintext credentials, so terminal, SFTP, Docker, metrics and
tunnels all work without per-subsystem changes. Sources are per user,
optionally shared, with the access token encrypted under the owner's
data key; resolved values are cached briefly in memory.

* style: format secret source changes

src/backend/tests/hosts/external-secrets.test.ts

@@ -0,0 +1,71 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+vi.mock("../../database/repositories/factory.js", () => ({
+  createCurrentSecretSourceRepository: () => ({
+    listVisibleToUser: async () => [],
+    decryptToken: () => "",
+  }),
+  createCurrentSettingsRepository: () => ({ get: async () => null }),
+}));
+
+const {
+  clearExternalSecretCache,
+  resolveExternalSecretRefs,
+  resolveSecretReference,
+} = await import("../../hosts/external-secrets.js");
+
+const source = {
+  id: "src-1",
+  userId: "alice",
+  name: "1P",
+  kind: "onepassword-connect",
+  baseUrl: "https://connect.internal",
+  token: "enc",
+  shared: false,
+  createdAt: "",
+  updatedAt: "",
+};
+
+describe("external secret references", () => {
+  beforeEach(() => clearExternalSecretCache());
+
+  it("replaces references in the host's secret fields and leaves plain secrets alone", async () => {
+    const resolver = vi.fn(async (_s, ref: string) => `resolved:${ref}`);
+    const host: Record<string, unknown> = {
+      password: "op://Infra/box/password",
+      key: "-----BEGIN OPENSSH PRIVATE KEY-----",
+      sudoPassword: "op://Infra/box/sudo",
+      username: "op://not-a-secret-field",
+    };
+    await resolveExternalSecretRefs(host, "alice", {
+      resolver,
+      pickSource: async () => source,
+    });
+    expect(host.password).toBe("resolved:op://Infra/box/password");
+    expect(host.sudoPassword).toBe("resolved:op://Infra/box/sudo");
+    expect(host.key).toBe("-----BEGIN OPENSSH PRIVATE KEY-----");
+    expect(host.username).toBe("op://not-a-secret-field");
+    expect(resolver).toHaveBeenCalledTimes(2);
+  });
+
+  it("caches a resolved reference per source for a minute", async () => {
+    const resolver = vi.fn(async () => "s3cret");
+    let clock = 1_000_000;
+    const deps = { resolver, pickSource: async () => source, now: () => clock };
+    await resolveSecretReference("alice", "op://v/i/f", deps);
+    await resolveSecretReference("alice", "op://v/i/f", deps);
+    expect(resolver).toHaveBeenCalledTimes(1);
+    clock += 61_000;
+    await resolveSecretReference("alice", "op://v/i/f", deps);
+    expect(resolver).toHaveBeenCalledTimes(2);
+  });
+
+  it("fails clearly when the user has no secret source", async () => {
+    await expect(
+      resolveSecretReference("bob", "op://v/i/f", {
+        resolver: async () => "x",
+        pickSource: async () => null,
+      }),
+    ).rejects.toThrow(/no secret source/);
+  });
+});