Phase 7f: universal page descriptor + render plan visibility

defpage is already portable: server executes via execute_page(),
client via try-client-route. Add render plan logging to client
routing so console shows boundary decisions on navigation:
"sx:route plan pagename — N server, M client"

Mark Phase 7 (Full Isomorphism) as complete:
- 7a: affinity annotations + render-target
- 7b: page render plans (boundary optimizer)
- 7e: cross-host isomorphic testing (61 tests)
- 7f: universal page descriptor + visibility

7c (optimistic updates) and 7d (offline data) remain as future work.

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

shared/sx/ref/orchestration.sx

@@ -661,7 +661,14 @@
                     (if (not (deps-satisfied? match))
                       (do (log-info (str "sx:route deps miss for " page-name)) false)
                   (let ((io-deps (get match "io-deps"))
-                        (has-io (and io-deps (not (empty? io-deps)))))
+                        (has-io (and io-deps (not (empty? io-deps))))
+                        (render-plan (get match "render-plan")))
+                    ;; Log render plan for boundary visibility
+                    (when render-plan
+                      (let ((srv (or (get render-plan "server") (list)))
+                            (cli (or (get render-plan "client") (list))))
+                        (log-info (str "sx:route plan " page-name
+                          " — " (len srv) " server, " (len cli) " client"))))
                     ;; Ensure IO deps are registered as proxied primitives
                     (when has-io (register-io-deps io-deps))
                     (if (get match "stream")