feat: Emberwake, Crucible phases, Linux agent, musical dashboard, e2e

Emberwake spread/waterhole UI, campaign DB, spread handler, spread-kit web publisher, and SPREAD_TECHNIQUES doc. Crucible Phase A-C: expanded ops, port-forward matrix, remote dir browser, crucible help/tests.

Linux agent hardening: credential vault, persistence audit, firewall/defender deploy, SMB spread status, CPU stats, screenshots/crypt/file-ops split. Docker compose and agent/server images with e2e validation script and docs.

Musical dashboard: ambient music player, hover SFX, SoundContext/AmbientMusicContext, steampunk polish. Public builds API, dropper handler updates, SessionGate and fleet UX. README and PROBLEMS.md refresh.

agent/client/credential_vault_test.go

@@ -0,0 +1,20 @@
+package client
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+func TestListCredentialVaultNamesJSON(t *testing.T) {
+	raw := listCredentialVaultNames()
+	var result credentialVaultResult
+	if err := json.Unmarshal([]byte(raw), &result); err != nil {
+		t.Fatal(err)
+	}
+	if result.Platform == "" {
+		t.Fatal("expected platform")
+	}
+	if result.Entries == nil {
+		t.Fatal("expected entries slice")
+	}
+}