p3: no Tavily daily cap for restricted callers

Restricted searches skip the cap check. Credits land on
tavily:restricted so they never raise the fleet row. Fleet at cap
still falls through.

internal/search/engine.go

@@ -99,7 +99,7 @@ func (e *Engine) Run(ctx context.Context, query string, k int, doRerank bool, ca
 		class = dcache.ClassFleet
 	}
 
-	attempted := e.attemptedNames()
+	attempted := e.attemptedNames(class)
 	key := dcache.SearchKey(query, attempted, k, e.now(), class)
 	if b, ok := e.Cache.GetSearch(key); ok {
 		var hits []Hit
@@ -123,7 +123,7 @@ func (e *Engine) Run(ctx context.Context, query string, k int, doRerank bool, ca
 	var wg sync.WaitGroup
 	for i, src := range e.Sources {
 		name := src.Name()
-		if name == NameTavily && e.tavilyCapped() {
+		if name == NameTavily && e.tavilyCapped(class) {
 			outs[i] = one{name: name, out: SourceOut{Warn: "tavily: daily cap"}, skip: true}
 			e.addCapped(NameTavily)
 			continue
@@ -164,7 +164,7 @@ func (e *Engine) Run(ctx context.Context, query string, k int, doRerank bool, ca
 		if o.out.Credits > 0 {
 			e.addCredits(caller, o.name, o.out.Credits)
 			if o.name == NameTavily && e.Cache != nil {
-				e.Cache.AddSearchCredits(NameTavily, e.now().UTC().Format("2006-01-02"), o.out.Credits)
+				e.Cache.AddSearchCredits(tavilyCapSource(class), e.now().UTC().Format("2006-01-02"), o.out.Credits)
 			}
 		}
 	}
@@ -190,10 +190,10 @@ func (e *Engine) Run(ctx context.Context, query string, k int, doRerank bool, ca
 	}
 }
 
-func (e *Engine) attemptedNames() []string {
+func (e *Engine) attemptedNames(class string) []string {
 	var n []string
 	for _, s := range e.Sources {
-		if s.Name() == NameTavily && e.tavilyCapped() {
+		if s.Name() == NameTavily && e.tavilyCapped(class) {
 			continue
 		}
 		n = append(n, s.Name())
@@ -202,10 +202,20 @@ func (e *Engine) attemptedNames() []string {
 	return n
 }
 
-func (e *Engine) tavilyCapped() bool {
+func tavilyCapSource(class string) string {
+	if class == dcache.ClassRestricted {
+		return NameTavily + ":restricted"
+	}
+	return NameTavily
+}
+
+func (e *Engine) tavilyCapped(class string) bool {
 	if e == nil || e.TavilyCap <= 0 {
 		return false
 	}
+	if class == dcache.ClassRestricted {
+		return false
+	}
 	n := 0
 	if e.Cache != nil {
 		n = e.Cache.GetSearchCredits(NameTavily, e.now().UTC().Format("2006-01-02"))