Document that secretFile/adminAccount.passwordFile are read as cfg.user

hortusfox-setup reads both files as cfg.user, not root. Pointing either
at an agenix/sops-nix secret without setting its owner/group to match
cfg.user/cfg.group fails the service with a permission error rather
than anything obviously related -- note it on both options.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

README.md

@@ -67,9 +67,9 @@ and a `services.hortusfox-web` NixOS module that wires the built package into a
 | `user` / `group` | string | `"hortusfox"` | System user/group the app and its phpfpm pool run as. |
 | `timezone` | string | `"UTC"` | App timezone (`APP_TIMEZONE`). |
 | `database.name` | string | `"hortusfox"` | MariaDB database name. |
-| `secretFile` | null or path | `null` | File of `KEY=VALUE` lines (`APP_KEY`, `SMTP_PASSWORD`, API keys, ...) appended verbatim onto the generated `.env` at runtime — not parsed, so it can carry arbitrary keys. Keep it out of the Nix store in production (agenix/sops-nix); a store path is fine for throwaway test configs. |
+| `secretFile` | null or path | `null` | File of `KEY=VALUE` lines (`APP_KEY`, `SMTP_PASSWORD`, API keys, ...) appended verbatim onto the generated `.env` at runtime — not parsed, so it can carry arbitrary keys. Keep it out of the Nix store in production (agenix/sops-nix); a store path is fine for throwaway test configs. Read by `hortusfox-setup`, which runs as the module's system user, not root — make sure its owner/group lets that user read it. |
 | `backupMaxAge` | null or string | `"1d"` | How long HortusFox's own export/auto-backup zips (`public/backup`, systemd-tmpfiles "age" syntax, e.g. `"1d"`, `"12h"`) are kept before auto-deletion. HortusFox names these with a fully predictable `hf_backup_<timestamp>.zip` pattern and serves them from the public webroot without ever cleaning them up itself, so anyone who knows or guesses the timestamp can otherwise download a full data export indefinitely. `null` disables cleanup entirely (not recommended for internet-facing deployments). |
-| `adminAccount.passwordFile` | null or path | `null` | Plaintext password file for a seeded initial admin account. HortusFox has no CLI/seed hook of its own and its only "create user" flow lives behind the admin panel, so without this a fresh deployment has no way to log in at all. Only takes effect on first boot; changing it later has no effect on an existing account. |
+| `adminAccount.passwordFile` | null or path | `null` | Plaintext password file for a seeded initial admin account. HortusFox has no CLI/seed hook of its own and its only "create user" flow lives behind the admin panel, so without this a fresh deployment has no way to log in at all. Only takes effect on first boot; changing it later has no effect on an existing account. Read by `hortusfox-setup` under the same non-root user as `secretFile` above. |
 | `adminAccount.username` | string | `"admin"` | Name for the seeded admin account — purely a display name, since HortusFox logs in by email rather than this field. |
 | `adminAccount.email` | string | `"admin@${domain}"` | Email for the seeded admin account. The default is just a guess at a real mailbox — set it to an address you actually control if you intend to use HortusFox's "Restore password" flow, which emails it. |
 | `settings` | attrs of str/int/bool | `{ }` | Extra/overriding `.env` entries, merged over the module's generated defaults (`settings` always wins). Note `php asatru` (used for migrations) only runs when `APP_DEBUG` is true, so migrations silently no-op unless it's set here or via `secretFile`. |

nixos-module/default.nix

@@ -229,7 +229,11 @@ in {
         File with secret KEY=VALUE lines (APP_KEY, SMTP_PASSWORD, API keys,
         ...) appended verbatim to the generated .env at runtime. Keep it out
         of the Nix store in production (e.g. agenix/sops-nix); a store path
-        is fine for throwaway test configs.
+        is fine for throwaway test configs. Read by hortusfox-setup, which
+        runs as cfg.user rather than root -- if you point this at an
+        agenix/sops-nix secret, make sure its owner/group is set to
+        cfg.user/cfg.group (or make it world-readable), or the service fails
+        with a permission error.
       '';
     };
 
@@ -261,7 +265,9 @@ in {
         a fresh deployment has no way to log in at all. Only used on first
         boot (guarded by the same stateDir/.installed marker as
         migrate:fresh); changing it afterwards has no effect on an
-        existing account.
+        existing account. Read by hortusfox-setup, which runs as cfg.user
+        rather than root -- as with secretFile, make sure this file's
+        owner/group lets cfg.user read it.
 
         Seeds a user (name set via adminAccount.username, email via
         adminAccount.email), bcrypt-hashed via