[codex] Harden context compression history handling (#848)

* Use token threshold for chat compression

* Add compression settings controls

* Use config for chat compression

* Cover protected messages in compression tests

* Remove message-count compression limit

* Harden compression window fallback

* Rebuild stale compression snapshots

* Harden stale compression snapshots

* Update changelog for compression hardening

* Prefer local history session details

packages/client/src/i18n/locales/fr.ts

@@ -549,6 +549,7 @@ jobTriggered: 'Job declenche',
       account: 'Compte',
       agent: 'Agent',
       memory: 'Memoire',
+      compression: 'Compression',
       session: 'Session',
       privacy: 'Confidentialite',
       apiServer: 'Serveur API',
@@ -599,6 +600,18 @@ jobTriggered: 'Job declenche',
       userCharLimit: 'Limite de caracteres du profil utilisateur',
       userCharLimitHint: 'Nombre maximum de caracteres pour USER.md',
     },
+    compression: {
+      enabled: 'Activer la compression',
+      enabledHint: 'Compresser automatiquement un long historique avant de depasser le contexte du modele',
+      threshold: 'Seuil de compression',
+      thresholdHint: 'Demarrer la compression quand les jetons estimes depassent ce ratio de contexte',
+      targetRatio: 'Ratio cible',
+      targetRatioHint: 'Taille cible de l\'historique apres compression comme ratio du contexte',
+      protectLastN: 'Proteger les messages recents',
+      protectLastNHint: 'Garder autant de messages recents non compresses',
+      protectFirstN: 'Proteger les premiers messages',
+      protectFirstNHint: 'Garder autant de premiers messages non compresses',
+    },
     session: {
       mode: 'Mode de reinitialisation',
       modeHint: 'Condition de declenchement de la reinitialisation de session',
@@ -952,6 +965,7 @@ jobTriggered: 'Job declenche',
     new_0_5_30_6: 'Harden Windows compatibility for path detection, file downloads, and job/update subprocesses so they no longer flash terminal windows',
     new_0_5_30_7: 'Fix config writes and provider presets: validate .env keys, route FUN-Codex through the Responses API, and refresh Z.AI/GLM model lists',
     new_0_5_30_8: 'Polish frontend details including collapsed sidebar layout, short group labels, sidebar divider, and conversation outline styling',
+    new_0_5_30_9: 'Context compression now follows Profile compression settings and hardens stale snapshots by reusing previous summaries with a safe tail instead of recompressing full history',
     new_0_5_5_1: '🎉 Joyeuse Fête du Travail! Pas de travail aujourd\'hui, merci de votre compréhension',
     new_0_5_5_2: 'Ajout d\'une page d\'historique pour les sessions Hermes',
     new_0_5_5_3: 'La page d\'historique gère les sessions de manière indépendante',