R-840: the config bundle — a signed agent_config_update brings a box's root-owned files (sudoers, wrappers, units)

felhom-os-apply gains mode 'bundle' (signed, verified by the wrapper itself against the root-owned
signers file — or, when that file is missing, only the installer's pinned key, which it then creates)
and --install-bundle (the installer's root entry). BUNDLE_FILES is the one table of paths; every check
(visudo, sh/bash -n, python, unit sections, RuntimeDirectory guard, nft -c, the route itself) runs
before the first write; a failed write or self-check puts every previous copy back. The trust root is
never a bundle path (R17). scripts/build-config-bundle.py builds it reproducibly; release-agent.sh
publishes it beside the binary. The agent reports the bundle record in system.config_bundle.
felhom-opsign signs agent_config_update. 43 wrapper tests (22 mutants red), Go executor tests.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

internal/hub/bundle_record_test.go

@@ -0,0 +1,25 @@
+package hub
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+// R-840: the agent reports the bundle record itself — "none" when no bundle ever reached the box (so an old wrapper
+// cannot hide that), "unknown" when it cannot be read, else the version and sha the root wrapper recorded.
+func TestReadBundleRecord(t *testing.T) {
+	dir := t.TempDir()
+	p := filepath.Join(dir, "config-bundle.json")
+	if got := string(readBundleRecord(p)); got != `{"version":"none"}` {
+		t.Fatalf("absent: %s", got)
+	}
+	os.WriteFile(p, []byte("{broken"), 0o644)
+	if got := string(readBundleRecord(p)); got != `{"version":"unknown"}` {
+		t.Fatalf("broken: %s", got)
+	}
+	os.WriteFile(p, []byte(`{"format":1,"agent_version":"0.143.0","bundle_sha256":"abc","installed_at":"2026-10-04T20:00:00Z","authority":"signed","files":{"/x":"y"}}`), 0o644)
+	if got := string(readBundleRecord(p)); got != `{"authority":"signed","bundle_sha256":"abc","installed_at":"2026-10-04T20:00:00Z","version":"0.143.0"}` {
+		t.Fatalf("record: %s", got)
+	}
+}