romm: database engine mariadb 11.4 -> 11.8, its own edge (proven on the bench AND on 9202)

After tonight's 5.3.0 -> 5.3.1 step (a separate commit, R-450). The engine
says "already upgraded to 11.8.9-MariaDB". Bench: seed read back; memory
watch 11 332 requests: romm's own memory 78 % of 768M (cgroup 84 %) — just
under the 80 % line, 0 kills; romm-db 26 %. Abort starts-and-serves.
Box (9202): done, read back, R-626 clean. 09 decision 21.

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

templates/romm/.felhom.yml

@@ -241,3 +241,4 @@ i18n:
 update_ladder:
   - {"from": {"romm": "rommapp/romm:5.0.0", "romm-db": "mariadb:11.4", "romm-redis": "redis:7-alpine"}, "to": {"romm": "rommapp/romm:5.3.0", "romm-db": "mariadb:11.4", "romm-redis": "redis:7-alpine"}, "digest": {"romm": "sha256:dc586cb3a2c7316fcffb3dc273171b1964523f0f409e989295d26d2199df1d4e", "romm-db": "sha256:70cc072b29b4a89ae07abb2d4da2c64678a7f2dfe092751bb51c87d67dc1338b", "romm-redis": "sha256:858f009f9709ce576febc734aa78b8f6d624b82571f9ddb6bda4377c833b3499"}, "verdict": "proven", "tested_at": "2026-09-21T19:27:03.627376+00:00", "harness_version": 1, "evidence": "felhom.eu/documentation/audits/update-night-2026-09-21/apps/romm/verdict.json", "memory_peak_pct": 80.9, "marks": {"files_may_change": false, "needs_person": null, "memory_tight": true}, "backfilled": "2026-09-23", "note": "backfilled from catalog commit 15f9ebf; box walk only (harness v1, no memory watch); digest = what the registry served on 2026-09-23, not a measurement of the tested image; memory watch from felhom.eu/documentation/audits/update-rulings-2026-09-23/harness/evidence/M1/verdict.json (bench, harness v2): peak 80.9%"}
   - {"from": {"romm": "rommapp/romm:5.3.0", "romm-db": "mariadb:11.4", "romm-redis": "redis:7-alpine"}, "to": {"romm": "rommapp/romm:5.3.1", "romm-db": "mariadb:11.4", "romm-redis": "redis:7-alpine"}, "digest": {"romm": "sha256:0d66b4ea152a237c7f24b95e87459f46d3c596a7c0b35a82f26bc971487278b3", "romm-db": "sha256:70cc072b29b4a89ae07abb2d4da2c64678a7f2dfe092751bb51c87d67dc1338b", "romm-redis": "sha256:858f009f9709ce576febc734aa78b8f6d624b82571f9ddb6bda4377c833b3499"}, "verdict": "proven", "tested_at": "2026-09-23T19:24:19Z", "harness_version": 3, "evidence": "felhom.eu/documentation/audits/night-2026-09-23/apps/romm/bench/evidence/MV-romm/verdict.json", "box_evidence": "felhom.eu/documentation/audits/night-2026-09-23/apps/romm/verdict.json", "memory_peak_pct": 79.5, "marks": {"files_may_change": false, "needs_person": null, "memory_tight": false}, "memory_basis": "cgroup_peak", "memory_cgroup_peak_pct": 79.5}
+  - {"from": {"romm": "rommapp/romm:5.3.1", "romm-db": "mariadb:11.4", "romm-redis": "redis:7-alpine"}, "to": {"romm": "rommapp/romm:5.3.1", "romm-db": "mariadb:11.8", "romm-redis": "redis:7-alpine"}, "digest": {"romm": "sha256:0d66b4ea152a237c7f24b95e87459f46d3c596a7c0b35a82f26bc971487278b3", "romm-db": "sha256:79d59758afc91b89b120b0a8904d637f5a3b3e1c4900f29b740d6d46c72fef68", "romm-redis": "sha256:858f009f9709ce576febc734aa78b8f6d624b82571f9ddb6bda4377c833b3499"}, "verdict": "proven", "tested_at": "2026-09-23T20:00:03Z", "harness_version": 3, "evidence": "felhom.eu/documentation/audits/night-2026-09-23/apps/romm-engine/bench/evidence/MV-romm/verdict.json", "box_evidence": "felhom.eu/documentation/audits/night-2026-09-23/apps/romm-engine/verdict.json", "memory_peak_pct": 78.0, "marks": {"files_may_change": false, "needs_person": null, "memory_tight": false}, "memory_basis": "anon", "memory_cgroup_peak_pct": 84.1}

templates/romm/docker-compose.yml

@@ -99,7 +99,7 @@ services:
       - "traefik.http.services.romm.loadbalancer.server.port=8080"
 
   romm-db:
-    image: mariadb:11.4
+    image: mariadb:11.8
     container_name: romm-db
     restart: unless-stopped
     environment: