Problem

In the desktop client you cannot click links that exist inside a journal (or any page). External markdown links — [label](https://…) — render as styled text but are completely inert: clicking them does nothing. There is no way to follow a URL you wrote in a block.

To be precise about scope (verified in the code):

So the gap is specifically external URLs. The renderer even admits it in a comment:

// MarkdownInline.tsx
// - `[label](url)` links (non-clickable for now, would need the Tauri opener plugin)

Why it's broken (root cause)

The token pipeline is fine — outl_md::inline tokenizes [text](url) into a Link { text, url } variant and it reaches the frontend with the href populated (InlineToken { kind: "link", value, href }). The break is everything after tokenization, on the desktop:

1. No click handler. In crates/outl-frontend-shared/src/markdown/MarkdownInline.tsx, the link case renders a plain <span> with no onClick (unlike ref and tag, which both call props.onRefClick / props.onTagClick). The href field is never read.
2. No callback. BlockCallbacks in crates/outl-desktop/src/components/BlockRow.tsx has onRefClick / onTagClick but no onLinkClick.
3. No Tauri capability / plugin. crates/outl-desktop/src-tauri/Cargo.toml has neither tauri-plugin-opener nor tauri-plugin-shell, and capabilities/default.json grants no opener:* / shell:* permission. So even with a handler there is no sanctioned way to open a URL in the system browser.
4. No backend command. There is no Tauri command that opens an external URL.

Expected behavior

Clicking an external [label](url) link inside a journal/page on the desktop should open the URL in the user's default browser (modifier-click could open in background — nice-to-have, not required).

Suggested fix

• Add tauri-plugin-opener (the modern replacement for the shell-open API) to src-tauri, register it, and grant opener:allow-open-url (scoped to http/https/mailto) in capabilities/default.json.
• Add an onLinkClick(href) prop threaded from OutlineView → BlockRow → <MarkdownInline />, wired to a small wrapper that calls the opener.
• Wire the link token in MarkdownInline.tsx to call it (with cursor-pointer + the existing link styling), guarding against non-http(s)/mailto schemes.

Notes / parity

The TUI also doesn't open external links today (ref_at_cursor has no Link variant), so this is a desktop-first feature — but it should be designed so the "open a URL" capability can be shared rather than reimplemented per client if the TUI/mobile later want it. The [[ref]] / #tag navigation already works on both and is out of scope here.