Start Housecarl: the logo, the wordmark and the skeleton

Housecarl will be a firewall manager for nftables, built the way Jarl and
Steward are: housecarld (a daemon with a REST API and web UI), hc (the
CLI) and SQLite.

- The logo: a carved Nordic doorway in Jarl's blue (artwork/logo.svg),
  with a small version without the carvings, lighter on dark
  backgrounds. scripts/logo.py builds the web UI's copies and
  scripts/banner.py the README banner.
- The HOUSECARL wordmark in Jarl's and Steward's angular letters, with
  new H, O, U and C (assets/brand.js), and the UI's color tokens.
- housecarld and hc print their version; the Makefile, version package,
  AGENTS.md, CHANGELOG and the design sketch (docs/design.md).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/logo.py

@@ -0,0 +1,53 @@
+#!/usr/bin/env python3
+# Builds the web UI's logo from the masters: artwork/logo.svg (a carved
+# Nordic doorway) and artwork/logo-small.svg (the same doorway without its
+# carvings, for small sizes). Each master is one evenodd path.
+#
+#   internal/web/static/assets/logo.svg  the favicon (a copy of the small one)
+#   internal/web/static/assets/logo.js   both paths for the web UI, which
+#                                        draws them inline (brand.js), so the
+#                                        logo appears together with the page
+#
+# It then runs scripts/banner.py to rebuild the README's banner. Run from
+# the repository root after changing a master:
+#
+#   python3 scripts/logo.py
+import json
+import os
+import shutil
+import subprocess
+import sys
+import xml.etree.ElementTree as ET
+
+MASTERS = {"full": "artwork/logo.svg", "small": "artwork/logo-small.svg"}
+OUT = "internal/web/static/assets"
+SVG = "{http://www.w3.org/2000/svg}"
+
+
+def read(path):
+    root = ET.parse(path).getroot()
+    paths = root.findall(f"{SVG}path")
+    if len(paths) != 1:
+        sys.exit(f"logo.py: {path} should hold exactly one <path>")
+    return root.attrib["viewBox"], paths[0].attrib["d"]
+
+
+def main():
+    found = {name: read(path) for name, path in MASTERS.items()}
+    views = {vb for vb, _ in found.values()}
+    if len(views) != 1:
+        sys.exit("logo.py: the full and small logos must share one viewBox")
+    with open(os.path.join(OUT, "logo.js"), "w") as f:
+        f.write("// The Housecarl logo, from artwork/logo.svg and artwork/logo-small.svg by\n"
+                "// scripts/logo.py; don't edit. brand.js draws it; logo.svg is the small one.\n"
+                f"export const viewBox = {json.dumps(views.pop())};\n"
+                f"export const full = {json.dumps(found['full'][1])};\n"
+                f"export const small = {json.dumps(found['small'][1])};\n")
+    shutil.copyfile(MASTERS["small"], os.path.join(OUT, "logo.svg"))
+    for name in ("logo.svg", "logo.js"):
+        print(f"{OUT}/{name}: {os.path.getsize(os.path.join(OUT, name))} bytes")
+    subprocess.run([sys.executable, "scripts/banner.py"], check=True)
+
+
+if __name__ == "__main__":
+    sys.exit(main())