secrets: migrate all hosts from sops to OpenBao vault

Replace sops-nix secrets with OpenBao vault secrets across all hosts.
Hardcode root password hash, add extractKey option to vault-secrets
module, update Terraform with secrets/policies for all hosts, and
create AppRole provisioning playbook.

Hosts migrated: ha1, monitoring01, ns1, ns2, http-proxy, nix-cache01
Wave 1 hosts (nats1, jelly01, pgdb1) get AppRole policies only.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

services/actions-runner/default.nix

@@ -1,8 +1,10 @@
 { pkgs, config, ... }:
 {
-  sops.secrets."actions-token-1" = {
-    sopsFile = ../../secrets/nix-cache01/actions_token_1;
-    format = "binary";
+  vault.secrets.actions-token = {
+    secretPath = "hosts/nix-cache01/actions-token";
+    extractKey = "token";
+    outputDir = "/run/secrets/actions-token-1";
+    services = [ "gitea-runner-actions1" ];
   };
 
   virtualisation.podman = {
@@ -13,7 +15,7 @@
   services.gitea-actions-runner.instances = {
     actions1 = {
       enable = true;
-      tokenFile = config.sops.secrets.actions-token-1.path;
+      tokenFile = "/run/secrets/actions-token-1";
       name = "actions1.home.2rjus.net";
       settings = {
         log = {