agent/endpoint: Manifest.Version() digest for skew detection

Order-independent fnv64a of the route set so a multi-node layer can tell
whether the nodes serving a deployment agree on the manifest (safe to route
without inspecting the path) or are mid rolling-deploy (fall back to a
path-aware resolve).

pkg/agent/endpoint/manifest.go

@@ -16,7 +16,9 @@ package endpoint
 
 import (
 	"fmt"
+	"hash/fnv"
 	"slices"
+	"strconv"
 	"strings"
 
 	"github.com/livekit/protocol/livekit"
@@ -37,6 +39,27 @@ type Manifest struct {
 	routes []Route
 }
 
+// Version is a stable fnv64a digest of the route set, used to detect manifest
+// skew across nodes serving the same deployment (all-agree => safe to route
+// without inspecting the path). It is order-independent: two workers on the
+// same revision hash identically regardless of route declaration order.
+func (m *Manifest) Version() uint64 {
+	lines := make([]string, 0, len(m.routes))
+	for i := range m.routes {
+		r := &m.routes[i]
+		methods := append([]string(nil), r.Methods...)
+		slices.Sort(methods)
+		lines = append(lines, strconv.Itoa(int(r.Kind))+" "+r.Template.String()+" "+strings.Join(methods, ",")+" "+strconv.FormatBool(r.Public))
+	}
+	slices.Sort(lines)
+	h := fnv.New64a()
+	for _, l := range lines {
+		_, _ = h.Write([]byte(l))
+		_, _ = h.Write([]byte{0})
+	}
+	return h.Sum64()
+}
+
 // MatchResult mirrors starlette's Match enum: a FULL match selects the route, a
 // PARTIAL match (path matched, method didn't) yields 405 only after the whole
 // table has been scanned, so a later route with the right method still wins.