Add orchestration test suite: 17 tests for Phase 7c+7d

Tests cover page data cache, optimistic cache update/revert/confirm,
offline connectivity tracking, offline queue mutation, and offline-aware
routing. Registered in test runner with mocked platform functions.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

sx/sx/nav-data.sx

@@ -126,6 +126,7 @@
   (dict :label "Renderer" :href "/testing/render")
   (dict :label "Dependencies" :href "/testing/deps")
   (dict :label "Engine" :href "/testing/engine")
+  (dict :label "Orchestration" :href "/testing/orchestration")
   (dict :label "Runners" :href "/testing/runners")))
 
 (define isomorphism-nav-items (list

sx/sxc/pages/docs.sx

@@ -648,6 +648,7 @@
     "render" (run-modular-tests "render")
     "deps" (run-modular-tests "deps")
     "engine" (run-modular-tests "engine")
+    "orchestration" (run-modular-tests "orchestration")
     :else (dict))
   :content (case slug
     "eval" (~testing-spec-content
@@ -692,6 +693,13 @@
       :spec-source spec-source
       :framework-source framework-source
       :server-results server-results)
+    "orchestration" (~testing-spec-content
+      :spec-name "orchestration"
+      :spec-title "Orchestration Tests"
+      :spec-desc "17 tests covering Phase 7c+7d orchestration — page data cache, optimistic cache update/revert/confirm, offline connectivity, offline queue mutation, and offline-aware routing."
+      :spec-source spec-source
+      :framework-source framework-source
+      :server-results server-results)
     "runners" (~testing-runners-content)
     :else (~testing-overview-content
       :server-results server-results)))