feat(doorman): badge listener + decoder TDD + deploy scaffolding [#355]

Modern successor of the 2018 Perl doorman (snapshot in legacy/):
bash+coreutils HID decoder, HA webhook dispatch, systemd unit.
Offline decoder suite green (9 tests); shellcheck zero-warning.

Umbrella #345. Work item: https://projects.knownelement.com/issues/355

scripts/pre-push

@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+# pre-push — full rule audit + clean-working-tree gate before pushing.
+# Installed via: bash scripts/setup-hooks.sh
+#
+# Combines two proven policies observed across projects:
+#   - KNEL-AIMiddleware: block push if the working tree is dirty.
+#   - RCEO-PersonalAssistant: block push if the full test suite fails.
+set -euo pipefail
+
+REPO_ROOT="$(git rev-parse --show-toplevel)"
+cd "$REPO_ROOT"
+
+echo "pre-push: running full rule audit..."
+
+# Full audit (non-fast): runs the slow test suite via `make test` if present.
+if ! bash scripts/check-rules.sh --quiet; then
+    echo ""
+    echo "pre-push audit FAILED. Push blocked."
+    echo "Re-run with output:  bash scripts/check-rules.sh"
+    echo "Bypass:              git push --no-verify   (emergencies only)"
+    exit 1
+fi
+
+echo "pre-push: all rules and tests passed."
+exit 0