Move the first five high-traffic scripts onto the core engine

Today's engine work reaches 30 of 561 ct scripts, about 5% of ProxmoxVE
traffic. The retry on engine downloads, exit 227 for a container that will not
start, the umask fix that stops a hardened host producing unusable containers,
the TMPDIR guard and the toolchain restore are all sitting where almost nobody
runs them.

Checked before touching anything, because "migrate" meant something much
larger last time:

  - None of the eighteen remaining top-25 scripts has an alpine-* variant, so
    there is no merge to do -- unlike the earlier round.
  - No script references misc/ anywhere except its bootstrap line.
  - Comparing the two engines' function surfaces, 61 names exist only in misc/.
    None of the eighteen calls any of them.

So it really is one line per script, and the head now matches the scripts
migrated earlier byte for byte.

Five in this wave rather than all eighteen, chosen as the lowest-volume of the
set at roughly 170 installs a day each: enough traffic to surface a problem
within a day, contained enough that a regression does not reach thousands.
docker at 1255/day and the OS containers should follow only once this wave has
run clean.

immich and vaultwarden are deliberately not in it. Both already sit near 44%
success, and migrating them now would change two variables at once with no way
to attribute the result.

ct/cloudflared.sh

@@ -1,5 +1,7 @@
 #!/usr/bin/env bash
-source <(curl -fsSL https://raw.githubusercontent.com/community-scripts/ProxmoxVE/main/misc/build.func)
+_CS_DEFAULT_URL="https://raw.githubusercontent.com/community-scripts/ProxmoxVE/main"
+_cs_boot="${COMMUNITY_SCRIPTS_CORE_DIR:-$(dirname "${BASH_SOURCE[0]}")/../../core}/core/build.func"
+source "$_cs_boot" 2>/dev/null || source <(curl -fsSL "${COMMUNITY_SCRIPTS_CORE_URL:-https://raw.githubusercontent.com/community-scripts/core/main}/core/build.func")
 # Copyright (c) 2021-2026 tteck
 # Author: tteck (tteckster)
 # License: MIT | https://github.com/community-scripts/ProxmoxVE/raw/main/LICENSE

ct/n8n.sh

@@ -1,5 +1,7 @@
 #!/usr/bin/env bash
-source <(curl -fsSL https://raw.githubusercontent.com/community-scripts/ProxmoxVE/main/misc/build.func)
+_CS_DEFAULT_URL="https://raw.githubusercontent.com/community-scripts/ProxmoxVE/main"
+_cs_boot="${COMMUNITY_SCRIPTS_CORE_DIR:-$(dirname "${BASH_SOURCE[0]}")/../../core}/core/build.func"
+source "$_cs_boot" 2>/dev/null || source <(curl -fsSL "${COMMUNITY_SCRIPTS_CORE_URL:-https://raw.githubusercontent.com/community-scripts/core/main}/core/build.func")
 # Copyright (c) 2021-2026 tteck
 # Author: tteck (tteckster)
 # License: MIT | https://github.com/community-scripts/ProxmoxVE/raw/main/LICENSE

ct/qbittorrent.sh

@@ -1,5 +1,7 @@
 #!/usr/bin/env bash
-source <(curl -fsSL https://raw.githubusercontent.com/community-scripts/ProxmoxVE/main/misc/build.func)
+_CS_DEFAULT_URL="https://raw.githubusercontent.com/community-scripts/ProxmoxVE/main"
+_cs_boot="${COMMUNITY_SCRIPTS_CORE_DIR:-$(dirname "${BASH_SOURCE[0]}")/../../core}/core/build.func"
+source "$_cs_boot" 2>/dev/null || source <(curl -fsSL "${COMMUNITY_SCRIPTS_CORE_URL:-https://raw.githubusercontent.com/community-scripts/core/main}/core/build.func")
 # Copyright (c) 2021-2026 community-scripts ORG
 # Author: tteck (tteckster) | Co-Author: Slaviša Arežina (tremor021)
 # License: MIT | https://github.com/community-scripts/ProxmoxVE/raw/main/LICENSE

ct/technitiumdns.sh

@@ -1,5 +1,7 @@
 #!/usr/bin/env bash
-source <(curl -fsSL https://raw.githubusercontent.com/community-scripts/ProxmoxVE/main/misc/build.func)
+_CS_DEFAULT_URL="https://raw.githubusercontent.com/community-scripts/ProxmoxVE/main"
+_cs_boot="${COMMUNITY_SCRIPTS_CORE_DIR:-$(dirname "${BASH_SOURCE[0]}")/../../core}/core/build.func"
+source "$_cs_boot" 2>/dev/null || source <(curl -fsSL "${COMMUNITY_SCRIPTS_CORE_URL:-https://raw.githubusercontent.com/community-scripts/core/main}/core/build.func")
 # Copyright (c) 2021-2026 tteck
 # Author: tteck (tteckster)
 # License: MIT | https://github.com/community-scripts/ProxmoxVE/raw/main/LICENSE

ct/uptimekuma.sh

@@ -1,5 +1,7 @@
 #!/usr/bin/env bash
-source <(curl -fsSL https://raw.githubusercontent.com/community-scripts/ProxmoxVE/main/misc/build.func)
+_CS_DEFAULT_URL="https://raw.githubusercontent.com/community-scripts/ProxmoxVE/main"
+_cs_boot="${COMMUNITY_SCRIPTS_CORE_DIR:-$(dirname "${BASH_SOURCE[0]}")/../../core}/core/build.func"
+source "$_cs_boot" 2>/dev/null || source <(curl -fsSL "${COMMUNITY_SCRIPTS_CORE_URL:-https://raw.githubusercontent.com/community-scripts/core/main}/core/build.func")
 # Copyright (c) 2021-2026 tteck
 # Author: tteck (tteckster)
 # License: MIT | https://github.com/community-scripts/ProxmoxVE/raw/main/LICENSE