Control-plane requests follow the lease but take no slot and write no row

Implemented-By: OpenCode session (model recorded in docs/implementer-log.md)

internal/proxy/control.go

@@ -0,0 +1,31 @@
+package proxy
+
+import (
+	"net/http"
+
+	"git.wntrmute.dev/kyle/crossbar/internal/config"
+)
+
+// isControlCall reports whether r is a control-plane call: a GET or HEAD on any allowed path, or a
+// POST to exactly /tokenize or /v1/chat/completions/control. Everything else — in particular a chat
+// completion on /v1/chat/completions — is not a control call. rest is the upstream path, not the
+// query string.
+func isControlCall(method, rest string) bool {
+	if method == http.MethodGet || method == http.MethodHead {
+		return true
+	}
+	return method == http.MethodPost && (rest == "/tokenize" || rest == "/v1/chat/completions/control")
+}
+
+// resolveModel returns the model for a request: the body's top-level "model" wins (already read by
+// peekModel), else the ?model= query parameter, else the route's default_model. The result keys the
+// lease and the limiter pair.
+func resolveModel(model string, r *http.Request, routeCfg config.Route) string {
+	if model == "" {
+		model = r.URL.Query().Get("model")
+	}
+	if model == "" {
+		model = routeCfg.DefaultModel
+	}
+	return model
+}