Makes the deploy account generic instead of per-project

No reason to mint a new system account for every project on the
same Pi - one shared, host-wide account works, namespaced by
directory per project underneath it.

aidlc-docs/features/gitea-deployment-workflow/operations/deployment/deployment-plan.md

@@ -28,10 +28,12 @@ Same physical host for both (per `infrastructure-design.md` § 1) — separated
 **Account model (revised at Deployment Setup)**: the Pi's existing `webadmin` account is FileZilla/
 SFTP-only, used by website-workspace authors uploading customer sites under
 `/mnt/storage1/www/html/` (`WEBSITE_WORKSPACE.md`'s role) — it cannot SSH in and stays that way. The
-deploy pipeline uses a **separate, dedicated** SSH-capable account instead
-(`deployment-instructions.md` § 1.2), so the two roles never overlap on one credential. Deploy paths
-live under that account's own home directory, not under `html/` — this was a deliberate choice to
-avoid the CMS's release/current/shared structure interfering with the other websites hosted there.
+deploy pipeline uses a **separate, generic, host-wide** SSH-capable account instead
+(`deployment-instructions.md` § 1.2) — not one created specifically for this project, since it may
+serve other projects' deploy pipelines on the same Pi too (reuse the reference project's existing
+account if it already has SSH access). Deploy paths live under that account's own home directory,
+namespaced per project, not under `html/` — this was a deliberate choice to avoid the CMS's
+release/current/shared structure interfering with the other websites hosted there.
 
 ## Rationale for What's Documented Here vs. Already Decided