fix(code): route all markdown link clicks through openExternal

[annikaschmid]

Summary

External https:// links rendered inside chat / agent messages were inert when clicked — they appeared correctly (with the external-link glyph), but did nothing. The regression was introduced in #2241, which added an onClick handler to the markdown <a> renderer for posthog-code:// deeplinks and short-circuited every other URL:

onClick={(event) => {
  if (!isDeeplink || !href) return;   // ← bails for normal http(s) URLs
  event.preventDefault();
  void trpcClient.os.openExternal.mutate({ url: href });
}}

For non-deeplink URLs the click was left to target="_blank" + the main process's setWindowOpenHandler fallback, which on at least some setups was not actually opening the URL in the system browser.

This change drops the isDeeplink guard so every link with a real href is routed through trpcClient.os.openExternal — the same path the deeplink branch already uses. setupExternalLinkHandlers in apps/code/src/main/window.ts remains as a defensive safety net for any stray navigations from elsewhere in the renderer.

The isPostHogCodeDeeplink import is still in use for markdownUrlTransform (so defaultUrlTransform doesn't strip the custom scheme); only the unused local in the a renderer was removed.

Test plan

• In a session, send a prompt that yields a markdown message containing a plain https:// link (e.g. ask the agent for a PostHog insight URL). Click the link → opens in the default system browser.
• Click a posthog-code:// deeplink (e.g. via Inbox → Discuss). Deeplink still routes correctly.
• Click a GitHub issue/PR URL in chat. GithubRefChip path is unaffected (returns before the modified onClick).
• Right-click a link → "Open link in new window" still does not spawn an Electron child window (setWindowOpenHandler returns action: "deny").

---

Created with PostHog Code

[greptile-apps]

_{Reviews (1): Last reviewed commit: "fix(code): route all markdown link click..." | Re-trigger Greptile}