platform: modularize api/gui, add docs-tests-web foundation, and refresh root config

selective-vpn-api/app/resolver_dns_policy.go

@@ -0,0 +1,32 @@
+package app
+
+import (
+	"sync"
+	"time"
+)
+
+type dnsAttemptPolicy struct {
+	TryLimit     int
+	DomainBudget time.Duration
+	StopOnNX     bool
+}
+
+type dnsCooldownState struct {
+	Attempts    int
+	TimeoutLike int
+	FailStreak  int
+	BanUntil    int64
+	BanLevel    int
+}
+
+type dnsRunCooldown struct {
+	mu               sync.Mutex
+	enabled          bool
+	minAttempts      int
+	timeoutRatePct   int
+	failStreak       int
+	banSec           int
+	maxBanSec        int
+	temporaryAsError bool
+	byUpstream       map[string]*dnsCooldownState
+}