Trino out of the code; commit messages name bands and rules

The rename step in init.sh and the guard in deploy/lib.sh are gone. README's
procedure is now "Removing the old project"; it keeps the old names until it
has run on the server. Migrations stay here (open point 8), and their README
says so. AGENTS.md adds the commit-message rule. Not deployed: live still runs
Trino.

Bands: 4 (Superset), persistence (docs). Rules: 2.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

deploy/lib.sh

@@ -94,11 +94,6 @@ load_artifacts() {
   while IFS= read -r line; do
     key=${line%%=*}
     value=${line#*=}
-    # A release from before 29 Oct 2026 still runs Trino, which logs in as
-    # `trino_ro`, since renamed `fuel_ro`: it cannot start (README "Rollback
-    # across the Trino removal").
-    [ "$key" != TRINO_CONFIG_HASH ] ||
-      die "$file is from before Trino was removed; see README \"Rollback across the Trino removal\""
     [[ $key =~ ^(SUPERSET_IMAGE_TAG|TRAEFIK_CONFIG_HASH)$ && $value =~ ^[0-9a-f]{16}$ ]] ||
       die "unexpected line in $file: $line"
     printf -v "$key" '%s' "$value"
@@ -143,7 +138,7 @@ preflight() {
   # The stack was the Compose project "fuel-monitoring" until 29 Oct 2026; "petrolyst" uses the
   # same data volumes, so both must never run at once (README "One-time steps after 29 Oct 2026").
   [ -z "$("${DOCKER[@]}" ps -aq --filter label=com.docker.compose.project=fuel-monitoring)" ] ||
-    die "containers of the old project fuel-monitoring exist; remove them first (README \"One-time steps after 29 Oct 2026\")"
+    die "containers of the old project fuel-monitoring exist; remove them first (README \"Removing the old project\")"
 }
 
 # promote <release> <sha>: make the release the live tree. --chmod applies to