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/vscode/webview/main.tsx

@@ -843,6 +843,18 @@ const handleLocalApiRequest = async (url: URL, init?: RequestInit) => {
     return new Response(JSON.stringify(updated), { status: 200, headers: { 'Content-Type': 'application/json' } });
   }
 
+  if (normalizedPathname === '/api/behavior/agents-md') {
+    if (method === 'GET') {
+      const data = await sendBridgeMessage('api:behavior/agents-md:get');
+      return new Response(JSON.stringify(data), { status: 200, headers: { 'Content-Type': 'application/json' } });
+    }
+    if (method === 'PUT') {
+      const body = init?.body ? JSON.parse(init.body as string) : {};
+      const data = await sendBridgeMessage('api:behavior/agents-md:save', body);
+      return new Response(JSON.stringify(data), { status: 200, headers: { 'Content-Type': 'application/json' } });
+    }
+  }
+
   if (pathname === '/api/magic-prompts') {
     if (method === 'GET') {
       const data = await sendBridgeMessage('api:magic-prompts:get');