chore: draft unreleased changelog, bump opencode sdk to 1.17.18

Changelog leads with the private relay and the native mobile apps (TestFlight
beta + Android APK links), followed by pairing v2 and the device management,
desktop multi-transport, and chat items; VS Code changelog gets the shared
chat-render entries.

packages/vscode/CHANGELOG.md

@@ -1,5 +1,8 @@
 ## [Unreleased]
 
+- Chat: Mermaid diagrams now have zoom controls (thanks to @c-w-xiaohei).
+- Chat: code blocks can show line numbers that stay aligned while streaming, and a new Wrap Code Block Lines setting controls long-line wrapping.
+- Chat: with Sticky User Header enabled, user messages no longer float over earlier messages in long conversations.
 - Chat: if sending a message times out or loses the connection after OpenCode accepted it, the extension now keeps the sent message instead of rolling it back as failed.
 
 ## [1.14.1] - 2026-07-07

packages/vscode/package.json

@@ -244,7 +244,7 @@
   },
   "dependencies": {
     "@openchamber/ui": "workspace:*",
-    "@opencode-ai/sdk": "1.17.12",
+    "@opencode-ai/sdk": "1.17.18",
     "adm-zip": "^0.5.16",
     "jsonc-parser": "^3.3.1",
     "react": "^19.1.1",