gitea-backup-pull: switch vlda-01 retention from a fixed count to a 30-day rotation

KEEP=30 (last 30 archives) approximated 30 days only if there was
exactly one dump per day. Prune by file mtime instead (find -mtime +30)
so a catch-up burst after time offline doesn't prematurely evict
recent dumps, and a quiet stretch doesn't hoard month-old ones.

README.md

@@ -479,8 +479,14 @@ The SSH keypair needed no special handling: Unraid already auto-mirrors
   relying on the file's own (nonexistent) `+x`.
 - Lands in `/mnt/disks/WSD2L840/git/` — an **Unassigned Device** (external
   disk, not part of the protected array), not the RAM-backed root — keeps
-  the last 30 locally, now the real long-term history given alpha deletes
+  a rolling 30 calendar days locally (by file `mtime`, not a fixed file
-  its own copies right after a verified pull.
+  count — a burst of catch-up pulls after being offline a while shouldn't
+  prematurely evict genuinely recent dumps, and a quiet stretch shouldn't
+  keep month-old ones around just for lack of newer arrivals), now the
+  real long-term history given alpha deletes its own copies right after a
+  verified pull. Verified live: a synthetic 40-day-old dump + its
+  checksum file were correctly pruned while a genuine 20-day-old one and
+  everything newer were left untouched.
 - **The device isn't guaranteed to already be mounted** when the script
   runs, so it resolves the disk by filesystem label (`findfs
   LABEL=WSD2L840`, not a hardcoded `/dev/sdX` — USB/Unassigned-Device

scripts/clients/vlda-01/README.md

@@ -39,7 +39,7 @@ of every script here, so it's worth stating plainly before anything else:
 
 | File here | Deployed path | Purpose |
 |---|---|---|
-| `user-scripts/gitea-backup-pull/script` | `/boot/config/plugins/user.scripts/scripts/gitea-backup-pull/script` | Pulls new `gitea-dump` archives from `alpha` via the restricted `giteabackup` SFTP account, verifies each one's sha256 checksum, deletes both files on `alpha` only after a confirmed match, prunes its own local retention (30). Resolves and mounts the `WSD2L840` Unassigned Device itself first, and unmounts it again afterward — but only if this run is the one that mounted it, never disturbing a mount it found already in place, and only if nothing else is using the disk at that moment (checked via `fuser -m`; `rc.unassigned umount`'s own lazy unmount never refuses on its own, so this script checks first and just leaves it mounted, no error, if something else is still on it). See the script's own header comment for the full reasoning. |
+| `user-scripts/gitea-backup-pull/script` | `/boot/config/plugins/user.scripts/scripts/gitea-backup-pull/script` | Pulls new `gitea-dump` archives from `alpha` via the restricted `giteabackup` SFTP account, verifies each one's sha256 checksum, deletes both files on `alpha` only after a confirmed match, prunes its own local retention (rolling 30 calendar days, by file `mtime` - not a fixed count). Resolves and mounts the `WSD2L840` Unassigned Device itself first, and unmounts it again afterward — but only if this run is the one that mounted it, never disturbing a mount it found already in place, and only if nothing else is using the disk at that moment (checked via `fuser -m`; `rc.unassigned umount`'s own lazy unmount never refuses on its own, so this script checks first and just leaves it mounted, no error, if something else is still on it). See the script's own header comment for the full reasoning. |
 | `user-scripts/gitea-backup-pull/description` | `.../gitea-backup-pull/description` | Shown in the User Scripts UI. |
 | `user-scripts/gitea-backup-pull-onboot/script` | `.../gitea-backup-pull-onboot/script` | One-line wrapper: `bash`-invokes the script above. Exists only because `schedule.json` supports one schedule per script *path* — this is how the "also run once at every restart" requirement was added alongside the existing daily `03:30` schedule without disturbing it. |
 | `user-scripts/gitea-backup-pull-onboot/description` | `.../gitea-backup-pull-onboot/description` | Shown in the User Scripts UI. |

scripts/clients/vlda-01/user-scripts/gitea-backup-pull/script

@@ -28,7 +28,7 @@ REMOTE_PORT=10022
 UD_LABEL=WSD2L840
 UD_MOUNTPOINT=/mnt/disks/WSD2L840
 LOCAL_DIR="$UD_MOUNTPOINT/git"
-KEEP=30
+KEEP_DAYS=30
 
 # WSD2L840 is an Unassigned Device, not part of the array - not
 # guaranteed to already be mounted when this runs. Resolve by label
@@ -150,11 +150,17 @@ if [ -s "$DEL_BATCH" ]; then
 	fi
 fi
 
-# prune to the last $KEEP archives (vlda-01 has far more headroom than
+# prune anything older than $KEEP_DAYS calendar days (vlda-01 has far
-# alpha, so this is the real long-term history now that alpha deletes
+# more headroom than alpha, so this is the real long-term history now
-# its own copies right after a verified pull)
+# that alpha deletes its own copies right after a verified pull). A
+# calendar-day window rather than a fixed count on purpose: a burst of
+# catch-up pulls after being offline a while shouldn't prematurely evict
+# genuinely recent dumps just because there are suddenly more than a
+# fixed count, and a quiet stretch with few new dumps shouldn't keep
+# month-old ones around just because too few newer ones have arrived to
+# push them out.
 cd "$LOCAL_DIR" || exit 1
-ls -1t gitea-dump-*.zip 2>/dev/null | tail -n +$((KEEP + 1)) | while read -r old; do
+find . -maxdepth 1 -name 'gitea-dump-*.zip' -mtime +"$KEEP_DAYS" -print0 | while IFS= read -r -d '' old; do
 	rm -f "$old" "${old}.sha256"
 done