R-444: weekly guest disk trim (pct fstrim) outside the night, under the heavy-op gate

Operator ruling 09 §3 decision 139. One exact sudoers rule FELHOM_FSTRIM
(`/usr/sbin/pct ^fstrim [0-9]+$`) + manifest entry guest-fstrim; new
internal/fstrim job: due Wednesday from 10:00 host-local, starts only
10:00-20:59, holds backup.InFlight (busy -> deferred to the next hourly
tick), failed trim retried at most 3x per week, bytes parsed from the
"(N bytes) trimmed" lines, last result per guest persisted in
<state_dir>/guest-disk-trim.json and reported as guest_disk_trim.
Config opt-out: "disk_trim": {"disable": true}.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

internal/capability/manifest.go

@@ -151,6 +151,10 @@ var manifest = []Capability{
 	// reboot-during-backup lock can't start → the customer box stays DOWN until this clears it) ----
 	{"stalelock-unlock", "reboot-during-backup stale-lock recovery", "/usr/sbin/pct", []string{"unlock", "9201"}, true, ""},
 
+	// ---- Weekly guest disk trim (FELHOM_FSTRIM, R-444). NON-critical: a missing grant means the thin pool is not
+	// reclaimed this week (the trim job WARNs per guest and the report shows the failure), not a serving outage. ----
+	{"guest-fstrim", "weekly guest disk trim (thin-pool reclaim, R-444)", "/usr/sbin/pct", []string{"fstrim", "9201"}, false, ""},
+
 	// ---- Offsite WG tunnel (FELHOM_WG, S3/v0.64.0; Critical FLIPPED in S4/v0.66.0 — offsite
 	// backups now RIDE the tunnel, so a degraded tunnel capability is operator-alert-worthy: the
 	// conf install, unit enable/restart and the handshake read gate the backup path. apt-install