feat(lanes): per-lane database, Redis, and .env isolation (A1+A2)

Gives each lane its own slot-derived runtime (ports, detached process
lifecycle, profile-driven hooks) and its own database/Redis logical
index/.env file, so two lanes running the same repo's stack at once no
longer share state. Machine-level DB/Redis credentials live at
~/.ccam/secrets.env (mode 0600, never returned by any route); a hook's
output is redacted of that password (raw and URL-encoded forms) before
it reaches a log file or the lane_hook_output websocket broadcast.
Wired into provision/up/reset/remove; reset accepts --keep-db to skip
the drop/recreate/migrate/reseed block entirely.

server/data/profile-templates/postgres-compose/hooks/db-drop.sh

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+# ─────────────────────────────────────────────────────────────────────────────
+# db-drop.sh – Drop this lane's Postgres database inside a docker-compose
+# service, via `dropdb --if-exists`. Ported verbatim from Shipyard's own
+# lane-reset / lane-remove scripts. CCAM only ever calls this with a name it
+# derived itself (server/lib/lane-services.js:dropDatabase), so this script
+# never needs to re-validate its argument.
+#
+# Called as: db-drop.sh <db-name>  (also available as $DB_NAME)
+# Requires/provides: same as db-create.sh in this same directory.
+# ─────────────────────────────────────────────────────────────────────────────
+# @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+set -euo pipefail
+
+NAME="${1:-$DB_NAME}"
+[ -n "$NAME" ] || { echo "db-drop: no database name given" >&2; exit 1; }
+
+docker compose -f "$COMPOSE_FILE" exec -T "$DB_SERVICE" dropdb --if-exists -U "$PG_USER" "$NAME"
+echo "db-drop: dropped $NAME (if it existed)"