weekly-health-digest: add internet speed check (section 4c)

Reports the speedtest-tracker (on .183) newest result: flags STALE if
>14h old (2+ missed 6h cycles → scheduler stalled) or LOW if the best
of the last 4 tests falls below the 500/500 Mbps floor (best-of-4 avoids
flagging a transient ISP dip). Floors adjustable. Local SQLite read.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

monitoring/weekly-health-digest.sh

@@ -191,6 +191,43 @@ for svc in lubelogger vaultwarden; do
     fi
 done
 
+# ── 4c. Internet speed (speedtest-tracker on .183) ──────────────────────────
+# Tracker records Ookla tests every 6h (SPEEDTEST_SCHEDULE). Flag if the newest
+# completed result is stale (>14h = 2+ missed cycles → scheduler stalled) or if
+# the best of the last 4 tests is below the floor (using best-of-4, not the
+# single latest, avoids flagging a transient ISP dip). Floors are ADJUSTABLE —
+# set to catch a real regression (e.g. the old 100Mb-uplink cap ≈ 94 Mbps) or
+# sustained ISP degradation, not normal variance. DB is local + tommy-readable.
+ST_DB="/home/tommy/speedtest-tracker/data/database.sqlite"
+ST_FLOOR_DOWN=500   # Mbps
+ST_FLOOR_UP=500     # Mbps
+if [ -r "$ST_DB" ]; then
+    st_row=$(sqlite3 "$ST_DB" "
+      SELECT
+        CAST((julianday('now') - julianday(max(created_at)))*24 AS INT) || '|' ||
+        CAST((SELECT download FROM results WHERE status='completed' ORDER BY id DESC LIMIT 1)*8/1e6 AS INT) || '|' ||
+        CAST((SELECT upload   FROM results WHERE status='completed' ORDER BY id DESC LIMIT 1)*8/1e6 AS INT) || '|' ||
+        CAST((SELECT max(download) FROM (SELECT download FROM results WHERE status='completed' ORDER BY id DESC LIMIT 4))*8/1e6 AS INT) || '|' ||
+        CAST((SELECT max(upload)   FROM (SELECT upload   FROM results WHERE status='completed' ORDER BY id DESC LIMIT 4))*8/1e6 AS INT)
+      FROM results WHERE status='completed';" 2>/dev/null)
+    st_age=$(echo "$st_row"  | cut -d'|' -f1)
+    st_dl=$(echo "$st_row"   | cut -d'|' -f2)
+    st_ul=$(echo "$st_row"   | cut -d'|' -f3)
+    st_mdl=$(echo "$st_row"  | cut -d'|' -f4)
+    st_mul=$(echo "$st_row"  | cut -d'|' -f5)
+    if [ -z "$st_age" ]; then
+        add_line "Internet speed" "no completed speedtest results found"
+    elif [ "$st_age" -gt 14 ]; then
+        add_line "Internet speed" "STALE — newest test ${st_age}h ago (expected every 6h; scheduler stalled?)"
+    elif [ "$st_mdl" -lt "$ST_FLOOR_DOWN" ] || [ "$st_mul" -lt "$ST_FLOOR_UP" ]; then
+        add_line "Internet speed" "LOW — best of last 4: ${st_mdl}/${st_mul} Mbps down/up (floor ${ST_FLOOR_DOWN}/${ST_FLOOR_UP})"
+    else
+        add_line "Internet speed" "OK" "${st_dl}/${st_ul} Mbps down/up, ${st_age}h ago"
+    fi
+else
+    add_line "Internet speed" "speedtest DB unreadable ($ST_DB)"
+fi
+
 # ── 5. Filesystem >85% ───────────────────────────────────────────────────────
 fs_over=$(prom_query '(1 - node_filesystem_avail_bytes{fstype!~"tmpfs|fuse.lxcfs|overlay|squashfs"} / node_filesystem_size_bytes{fstype!~"tmpfs|fuse.lxcfs|overlay|squashfs"}) * 100 > 85' | python3 -c "
 import json,sys