Make the workspace right pane a first-class tab host (#3287)

* feat(app): add persistent workspace side panes

Keep the common review and file-browsing workflow beside the active agent without tearing down pane contents. Workspace tabs now share one compact chip language, assistant file links route into the retained right pane, and diff/file trees share stable geometry.

* fix(app): localize pull request empty state

* test(app): update explorer pane coverage

* fix(app): preserve explorer pane workflows

* test(app): make explorer tab selection idempotent

* fix(app): persist workspace review pins

* fix(app): preserve sidebar scrim drag hook

* fix(app): restore companion pane interactions

* test(app): follow selected sidebar surface

packages/app/src/i18n/resources/fr.ts

@@ -592,6 +592,7 @@ export const fr: TranslationResources = {
         renameAgent: "Renommer l'agent",
       },
       actions: {
+        newTab: "Nouvel onglet",
         newAgent: "Nouvel agent",
         newTerminal: "Nouveau terminal",
         preparingTerminal: "Préparation de l'onglet du terminal",
@@ -600,6 +601,9 @@ export const fr: TranslationResources = {
         exitFocusMode: "Quitter le mode concentration",
         splitRight: "Volet divisé à droite",
         splitDown: "Diviser le volet vers le bas",
+        changes: "Modifications",
+        files: "Fichiers",
+        pullRequest: "Demande de fusion",
         terminalProfilesMenu: "Terminal profiles",
         editTerminalProfiles: "Edit profiles…",
         pinTarget: "Épingler",
@@ -1705,6 +1709,18 @@ export const fr: TranslationResources = {
         reloadMessage: "Vos modifications locales seront perdues.",
       },
     },
+    files: {
+      label: "Fichiers",
+      subtitle: "Fichiers de l’espace de travail",
+      tooltip: "Parcourir les fichiers de l’espace de travail",
+    },
+    pullRequest: {
+      label: "Demande de fusion",
+      subtitle: "Détails de la demande de fusion",
+      emptyTitle: "Aucune demande de fusion pour le moment",
+      emptyDescription:
+        "Créez une demande de fusion pour cette copie de travail afin d’afficher ses détails ici.",
+    },
     diff: {
       changesLabel: "Modifications",
       changesSubtitle: "Différences de l'arbre de travail",