feat: add Behavior settings page for global AGENTS.md (#1079)

* feat: add Behavior settings page for global AGENTS.md

- Add new 'Behavior' settings page to manage global system prompt
- Sync global behavior prompt to ~/.config/opencode/AGENTS.md
- Add GET/PUT /api/behavior/agents-md endpoints with 1MB size limit
- Add AbortController guards and parallel fetches in BehaviorPage
- Add i18n translations for en, es, ko, pt-BR, uk, zh-CN
- Add globalBehaviorPrompt to DesktopSettings type and sanitizer
- Add /api/behavior to express.json() body-parser whitelist
- Ensure atomic save: AGENTS.md written before settings updated

* fix: address Greptile review feedback

- Rename misleading 'trimmed' variable to 'value' in settings-helpers.js
- Add Content-Length guard for /api/behavior before 50mb JSON parser
- Use express.json({ limit: '1mb' }) for behavior endpoints
- Add actual translations for es, ko, pt-BR, uk, zh-CN locales

* fix(vscode): support behavior settings endpoint

* fix(behavior): wait for settings persistence

* fix(behavior): end agents file with newline

* fix(behavior): avoid duplicate textarea resize handles

* fix(behavior): clarify global rules copy

* fix(behavior): move rules note into tooltip

---------

Co-authored-by: Bohdan Triapitsyn <artmore@protonmail.com>

packages/ui/src/lib/i18n/messages/ko.settings.ts

@@ -337,6 +337,14 @@ export const settingsDict = {
   'settings.agents.page.permissions.addCustomRule': '사용자 정의 규칙 추가',
   'settings.agents.page.permissions.permissionPlaceholder': '권한...',
   'settings.agents.page.permissions.patternPlaceholder': '패턴(예: *)',
+  'settings.page.behavior.title': '동작',
+  'settings.behavior.page.title': '동작',
+  'settings.behavior.page.warning.title': '전역 규칙은 프로젝트 규칙과 함께 사용됩니다',
+  'settings.behavior.page.warning.description': '여기에서 변경한 내용은 {path}를 업데이트합니다. 프로젝트 수준의 AGENTS.md가 있으면 OpenCode도 함께 포함합니다.',
+  'settings.behavior.page.section.systemPrompt': '전역 AGENTS.md',
+  'settings.behavior.page.field.systemPromptPlaceholder': '당신은 유용한 AI 어시스턴트입니다...\n\n모든 세션과 공급자에서 AI가 어떻게 행동해야 하는지에 대한 절대적인 규칙을 정의할 수 있습니다.',
+  'settings.behavior.page.toast.saved': '동작이 성공적으로 저장되었습니다',
+  'settings.behavior.page.toast.saveFailed': '동작 저장에 실패했습니다',
   'settings.commands.sidebar.title': '명령어',
   'settings.commands.sidebar.total': '총 {count}개',
   'settings.commands.sidebar.empty.title': '설정된 명령어가 없습니다',