feat(install): make backups optional via INSTALL_BACKUPS prompt

Adds top-level y/n gate before the B2 prompt block in 00-base.sh.
When INSTALL_BACKUPS=no:
  - 50-backups.sh exits 0 immediately (and removes any previously
    installed /usr/local/bin/backup.sh + /etc/cron.d/serverdeploy-backup
    so toggling off actually uninstalls)
  - No restic password file generated
  - No nightly cron

GeoIP was already optional (GEOIP_ENABLED=no path was already
implemented in 45-geoip.sh, monitoring guards on GEOIP_ENABLED, and
10-caddy.sh writes a no-op (geoblock) placeholder so 'import geoblock'
in site files keeps working) — no changes needed there.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: qfiber

bootstrap/00-base.sh

@@ -288,15 +288,20 @@ else
             "RU,CN,BY,AU,IN,NG,KP"
     fi
 
-    # ---- Backblaze B2 ----
+    # ---- Backups (restic → Backblaze B2) ----
     echo
-    info "Backblaze B2 backups (leave empty to configure later)"
-    prompt B2_BUCKET "B2 bucket name" ""
+    info "Nightly backups (restic → Backblaze B2): encrypted, 7 daily + 12 monthly snapshots."
+    prompt_yes_no INSTALL_BACKUPS "Install backups?" "y"
+    B2_BUCKET=""
     B2_ACCOUNT_ID=""
     B2_ACCOUNT_KEY=""
-    if [[ -n "${B2_BUCKET}" ]]; then
-        prompt_required B2_ACCOUNT_ID  "B2 application key ID"
-        prompt_secret    B2_ACCOUNT_KEY "B2 application key"
+    if [[ "${INSTALL_BACKUPS}" == "yes" ]]; then
+        info "B2 credentials (leave bucket empty to install the backup script now and add creds later)"
+        prompt B2_BUCKET "B2 bucket name" ""
+        if [[ -n "${B2_BUCKET}" ]]; then
+            prompt_required B2_ACCOUNT_ID  "B2 application key ID"
+            prompt_secret    B2_ACCOUNT_KEY "B2 application key"
+        fi
     fi
 
     echo
@@ -397,6 +402,7 @@ PMA_HOST="${PMA_HOST}"
 PGA_HOST="${PGA_HOST}"
 
 # === Backups (Backblaze B2) ===
+INSTALL_BACKUPS="${INSTALL_BACKUPS}"
 B2_ACCOUNT_ID="${B2_ACCOUNT_ID}"
 B2_ACCOUNT_KEY="${B2_ACCOUNT_KEY}"
 B2_BUCKET="${B2_BUCKET}"

bootstrap/50-backups.sh

@@ -17,6 +17,13 @@ source "${REPO_DIR}/lib/common.sh"
 require_root
 load_config
 
+if [[ "${INSTALL_BACKUPS:-yes}" != "yes" ]]; then
+    info "Backups not selected (INSTALL_BACKUPS=${INSTALL_BACKUPS:-no}) — skipping."
+    # Tear down a previous install if the operator turned backups off
+    rm -f /etc/cron.d/serverdeploy-backup /usr/local/bin/backup.sh
+    exit 0
+fi
+
 RESTIC_PASSWORD_FILE=/etc/serverdeploy/restic.password
 BACKUP_SCRIPT=/usr/local/bin/backup.sh