feat: add toolchain harness for the 11 Arcline Go tools

Harness that clones the 11 Go tools (arcline-uptime, -check, -audit,
-dns, -vault, -email, -migrate, -billing, -portal, -website, -status)
from git.arcline.it, builds release binaries, and packages each into a
.deb that configure-system installs into the image. Tools that cannot
be fetched or built are skipped without breaking the OS build.

toolchain/README.md

@@ -0,0 +1,30 @@
+# Arcline OS — toolchain packaging
+#
+# The landing page promises 11 Go tools shipping with Arcline OS. This harness
+# turns each tool's source repo into a .deb package that configure-system.sh
+# installs into the image.
+#
+# Tools (source of truth: tools.list):
+#
+#   arcline-uptime   HTTP/TCP/TLS/DNS monitoring, Prometheus metrics export
+#   arcline-check    CDN + transparency auditor
+#   arcline-audit    full site health scanner (SSL, headers, perf, a11y)
+#   arcline-dns      DNS propagation checker across resolvers
+#   arcline-vault    encrypted secrets store (REST API + CLI)
+#   arcline-email    self-hosted SMTP/IMAP stack (OpenSMTPD + Dovecot + Rspamd)
+#   arcline-migrate  cPanel/Plesk → Arcline migration
+#   arcline-billing  Stripe-powered subscription management
+#   arcline-portal   customer dashboard (SSL monitoring + ticketing)
+#   arcline-website  Go HTTP server for arcline.it
+#   arcline-status   static status page generator
+#
+# Usage:
+#   toolchain/build-tools.sh                  # build all (clone from git.arcline.it)
+#   ARCLINE_TOOLS_DIR=/path/to/checkouts \    # reuse local checkouts
+#     toolchain/build-tools.sh
+#   make toolchain
+#
+# The script is a harness ("the wires"): it clones each repo, tries a handful
+# of common Go layouts, builds a release binary, and packages a .deb. Any tool
+# whose repo is unavailable or fails to build is skipped with a warning — the
+# build must not silently break the OS image.