Merge remote-tracking branch 'origin/main' into claude/spelunk-api-key-tenant-6373cf

docs/manual-checks.md

@@ -3538,3 +3538,16 @@ Register a device, sync something, then `sudo dnf remove dodossh`.
 make an uninstall delete a user's un-synced work — the Linux spelling of the mistake ADR 0013 decision 2
 exists to prevent. Files left behind under `/opt/DodoSSH` are files the package did not own, which means
 something wrote into the install directory at runtime and would survive a reinstall.
+
+### 19.13 A copy at the same path that rpm does not own is offered nothing
+
+On a distribution without rpm — Arch, say, with a locally built package that puts the nightly tree at
+`/opt/DodoSSH.Nightly` — open PREFERENCES → UPDATES.
+
+**Pass:** **CHECK NOW** is disabled and the row says this copy was installed outside the `dodossh-nightly`
+RPM and should be updated with the package manager that installed it. `~/.local/share/dodossh.nightly/updates/`
+stays empty however long it runs.
+
+**Failure means:** a banner offering a nightly is the path being taken as proof the RPM is installed, or an
+rpm that cannot answer being read as an old version — the fault this check was written for, which offered
+every nightly as newer and fetched a 56 MB package the machine could never install, every six hours.