release(v1.7.31-alpha): idempotent IndeedHub install + auto-merge default mirrors/registries + 3rd OVH update mirror

- Backend: install.rs registry reachability probe now strips the
  `host[:port]/namespace` suffix before appending `/v2/` (the Docker
  V2 API lives at the host root, not under the namespace) and accepts
  HTTP 405 in addition to 200/401 as "registry daemon alive". This
  fixes false "unreachable" reports on the Test button for Gitea and
  other registries that protect their /v2/ endpoint.
- Backend: stacks.rs install_indeedhub_stack now force-removes any
  leftover indeedhub-* containers and indeedhub-net before creating
  the stack. A partial install (or the old first-boot stub racing the
  installer) used to leave containers around that blocked re-install
  with "name already in use". Re-running the App Store install now
  self-heals.
- Backend: registry.rs load_registries auto-merges any default
  registry URLs missing from the saved config (appended with priority
  max+10+i, persisted). Lets new default mirrors (e.g. Server 3 OVH)
  roll out to existing nodes without manual config edits. Explicit
  removals still stick — URLs absent from disk AND absent from
  defaults stay gone.
- Backend: update.rs adds DEFAULT_TERTIARY_MIRROR_URL at
  http://146.59.87.168:3000/ (Server 3 OVH) to default_mirrors, with
  the same auto-merge-on-load behavior as registries. Test updated
  for 3-mirror default (.160, tx1138, .168).
- Scripts: dropped the first-boot IndeedHub stub (~38 lines in
  first-boot-containers.sh §8b). It predated the proper stack
  installer, raced it, and was the main source of the name-conflict
  mess the stacks.rs cleanup above now also guards against.

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

scripts/first-boot-containers.sh

@@ -1216,44 +1216,6 @@ if $DOCKER images --format '{{.Repository}}:{{.Tag}}' 2>/dev/null | grep -q 'str
   fi
 fi
 
-# 8b. Indeehub (pull from registry, or use local build)
-if ! $DOCKER ps --format '{{.Names}}' 2>/dev/null | grep -q indeedhub; then
-  # Use image-versions.sh variable if sourced, otherwise detect
-  if [ -z "${INDEEDHUB_IMAGE:-}" ]; then
-    INDEEDHUB_IMAGE=""
-    # Try local image first (pre-built or loaded from ISO)
-    if $DOCKER images --format '{{.Repository}}:{{.Tag}}' 2>/dev/null | grep -q 'localhost/indeedhub'; then
-      INDEEDHUB_IMAGE="localhost/indeedhub:local"
-    # Try pinned registry image
-    elif $DOCKER pull "$ARCHY_REGISTRY/indeedhub:1.0.0" --tls-verify=false 2>>"$LOG"; then
-      INDEEDHUB_IMAGE="$ARCHY_REGISTRY/indeedhub:1.0.0"
-    fi
-  fi
-  if [ -n "$INDEEDHUB_IMAGE" ]; then
-    log "Creating Indeehub from $INDEEDHUB_IMAGE..."
-    $DOCKER run -d --name indeedhub --restart unless-stopped \
-      --network archy-net --network-alias indeedhub \
-      --health-cmd="curl -sf http://localhost:7777/health || exit 1" --health-interval=120s --health-timeout=5s --health-retries=3 \
-      --memory=$(mem_limit indeedhub) \
-      --cap-drop ALL --security-opt no-new-privileges:true \
-      --tmpfs /tmp:rw,noexec,nosuid,size=64m \
-      -p 7778:7777 \
-      "$INDEEDHUB_IMAGE" 2>>"$LOG" || true
-    # Fix IndeedHub for iframe: remove X-Frame-Options so it loads in Archipelago panel
-    sleep 2
-    if $DOCKER ps --format '{{.Names}}' 2>/dev/null | grep -q "^indeedhub$"; then
-      $DOCKER exec indeedhub sed -i "/X-Frame-Options/d" /etc/nginx/conf.d/default.conf 2>/dev/null || true
-      # Fix Host header for NIP-98 auth — $host strips port, $http_host preserves it
-      $DOCKER exec indeedhub sed -i 's|proxy_set_header Host $host;|proxy_set_header Host $http_host;|g' /etc/nginx/conf.d/default.conf 2>/dev/null || true
-      if [ -f /opt/archipelago/web-ui/nostr-provider.js ]; then
-        $DOCKER cp /opt/archipelago/web-ui/nostr-provider.js indeedhub:/usr/share/nginx/html/nostr-provider.js 2>/dev/null || true
-      fi
-      $DOCKER exec indeedhub nginx -s reload 2>/dev/null || true
-      log "Applied IndeedHub iframe fix (X-Frame-Options, Host header, nostr-provider)"
-    fi
-  fi
-fi
-
 # 9. Custom UI containers (bitcoin-ui, lnd-ui)
 # These are built from Dockerfiles in /opt/archipelago/docker/ or loaded from pre-built images.