♻️ Reuse embed param for exporter static renders

The bitmap and svg renderers requested image embedding with a new
render-embed parameter while the render entrypoint already supports
an equivalent one, so both were semantically duplicated knobs.

- switch exporters to the existing :embed parameter
- drop the render-embed schema entry and resolution logic
- populate the images cache only when embedding is active so non
  embedding consumers do not download every object image upfront

SVG exports of shapes with image fills now contain embedded data
uris instead of url references; this restores the original intent
of the exporter rewrite and keeps svg and bitmaps deterministic.

AI-assisted-by: glm-5.3-flash

exporter/src/app/renderer/bitmap.cljs

@@ -58,9 +58,9 @@
     (p/let [params {:file-id file-id
                     :page-id page-id
                     :share-id share-id
+                    :embed true
                     :object-id (mapv :id objects)
                     :route "objects"
-                    :render-embed true
                     :skip-children skip-children
                     :wasm (when is-wasm "true")
                     :scale scale}

exporter/src/app/renderer/svg.cljs

@@ -345,7 +345,7 @@
     (p/let [params {:file-id file-id
                     :page-id page-id
                     :share-id share-id
-                    :render-embed true
+                    :embed true
                     :object-id (mapv :id objects)
                     :route "objects"}
             uri    (-> (cf/get-internal-uri)

frontend/src/app/render.cljs

@@ -126,7 +126,7 @@
                :skip-children skip-children}]]))))))
 
 (defn- fetch-objects-bundle
-  [& {:keys [file-id page-id share-id object-id] :as options}]
+  [& {:keys [file-id page-id share-id object-id embed?] :as options}]
   (ptk/reify ::fetch-objects-bundle
     ptk/WatchEvent
     (watch [_ state _]
@@ -146,10 +146,16 @@
              (rx/map (fn [objects]
                        (render/adapt-objects-for-shape objects object-id)))
              (rx/merge-map (fn [objects]
-                             (rx/concat
-                              (->> (render/populate-images-cache objects)
-                                   (rx/ignore))
-                              (rx/of #(assoc % :objects objects))))))))))
+                             (if-not embed?
+                               (rx/of #(assoc % :objects objects))
+
+                               ;; Populate the images cache before rendering so
+                               ;; data-uri substitutions are instantly available
+                               ;; on the first paint.
+                               (rx/concat
+                                (->> (render/populate-images-cache objects)
+                                     (rx/ignore))
+                                (rx/of #(assoc % :objects objects)))))))))))
 
 (def ^:private schema:render-objects
   [:map {:title "render-objets"}
@@ -157,7 +163,6 @@
    [:file-id ::sm/uuid]
    [:share-id {:optional true} ::sm/uuid]
    [:embed {:optional true} :boolean]
-   [:render-embed {:optional true} :boolean]
    [:skip-children {:optional true} :boolean]
    [:object-id
     [:or [::sm/set ::sm/uuid] ::sm/uuid]]])
@@ -173,10 +178,13 @@
 (defn- render-objects
   [params]
   (try
-    (let [{:keys [file-id page-id embed render-embed share-id object-id skip-children wasm scale] :as params}
-          (coerce-render-objects-params params)
-          embed (if (some? render-embed) render-embed embed)]
-      (st/emit! (fetch-objects-bundle :file-id file-id :page-id page-id :share-id share-id :object-id object-id))
+    (let [{:keys [file-id page-id embed share-id object-id skip-children wasm scale] :as params}
+          (coerce-render-objects-params params)]
+      (st/emit! (fetch-objects-bundle :file-id file-id
+                                      :page-id page-id
+                                      :share-id share-id
+                                      :object-id object-id
+                                      :embed? embed))
       (if (uuid? object-id)
         (mf/html
          [:& object-svg