🐛 Strip nil values at text-style merge boundaries

Add d/without-nils at every point where default-font or editor styles
are merged before being stored or used to build content:

- v2-update-text-editor-styles and v3-update-text-editor-styles now
  strip nils from merged styles before writing to workspace state.
- initialize-editor-state strips nils from the attrs passed to Draft.js.
- v2-default-text-content strips nils from default-font before building
  the initial text tree for new shapes.

These are defensive guards so that any residual nil in default-font
(e.g. from sessions predating the save-font fix) cannot reach shape
content or editor state.

frontend/src/app/main/data/workspace/texts.cljs

@@ -183,8 +183,9 @@
     ptk/UpdateEvent
     (update [_ state]
       (let [text-state   (some->> content ted/import-content)
-            attrs        (merge (txt/get-default-text-attrs)
-                                (get-in state [:workspace-global :default-font]))
+            attrs        (d/without-nils
+                          (merge (txt/get-default-text-attrs)
+                                 (get-in state [:workspace-global :default-font])))
             editor       (cond-> (ted/create-editor-state text-state decorator)
                            (and (nil? content) (some? attrs))
                            (ted/update-editor-current-block-data attrs))]
@@ -945,9 +946,10 @@
       ;; `stylechange` can fire on every `selectionchange` while typing.
       ;; Avoid swapping the global store when the computed styles are unchanged,
       ;; otherwise we can end up in store->rerender->selectionchange loops.
-      (let [merged-styles (merge (txt/get-default-text-attrs)
-                                 (get-in state [:workspace-global :default-font])
-                                 new-styles)
+      (let [merged-styles (d/without-nils
+                           (merge (txt/get-default-text-attrs)
+                                  (get-in state [:workspace-global :default-font])
+                                  new-styles))
             prev (get-in state [:workspace-v2-editor-state id])]
         (if (= merged-styles prev)
           state

frontend/src/app/main/data/workspace/texts_v3.cljs

@@ -6,6 +6,7 @@
 
 (ns app.main.data.workspace.texts-v3
   (:require
+   [app.common.data :as d]
    [app.common.types.text :as txt]
    [potok.v2.core :as ptk]))
 
@@ -14,7 +15,8 @@
   (ptk/reify ::v3-update-text-editor-styles
     ptk/UpdateEvent
     (update [_ state]
-      (let [merged-styles (merge (txt/get-default-text-attrs)
-                                 (get-in state [:workspace-global :default-font])
-                                 new-styles)]
+      (let [merged-styles (d/without-nils
+                           (merge (txt/get-default-text-attrs)
+                                  (get-in state [:workspace-global :default-font])
+                                  new-styles))]
         (update-in state [:workspace-wasm-editor-styles id] (fnil merge {}) merged-styles)))))

frontend/src/app/util/text/content.cljs

@@ -6,6 +6,7 @@
 
 (ns app.util.text.content
   (:require
+   [app.common.data :as d]
    [app.common.types.text :as txt]
    [app.main.refs :as refs]
    [app.util.text.content.from-dom :as fd]
@@ -26,7 +27,7 @@
   current default typography. Used by the V2 editor/WASM path when a shape is
   created with no content yet."
   []
-  (let [default-font  (deref refs/default-font)
+  (let [default-font  (d/without-nils (deref refs/default-font))
         text-defaults (merge (txt/get-default-text-attrs) default-font)
         default-span  (merge {:text ""}
                              (select-keys text-defaults txt/text-node-attrs))