fix(tui): wrap markdown links in Link so Ghostty/iTerm/kitty get real OSC 8 hyperlinks

renderLink was discarding the URL entirely — it rendered the label as amber
underlined text and dropped the href. Result: Cmd+Click / Ctrl+Click did
nothing in any terminal, including Ghostty.

Now both markdown links `[label](url)` and bare `https://…` URLs are wrapped
in @hermes/ink's Link component, which emits OSC 8 (\\x1b]8;;url\\x07label\\x1b]8;;\\x07)
when supportsHyperlinks() returns true. ADDITIONAL_HYPERLINK_TERMINALS already
includes ghostty, iTerm2, kitty, alacritty, Hyper.

Autolinks that look like bare emails (foo@bar.com) now prepend mailto: in the
href so they open the mail client correctly.

Also adds a typed declaration for Link in hermes-ink.d.ts.

ui-tui/src/types/hermes-ink.d.ts

@@ -63,6 +63,11 @@ declare module '@hermes/ink' {
   export const Box: React.ComponentType<any>
   export const AlternateScreen: React.ComponentType<any>
   export const Ansi: React.ComponentType<any>
+  export const Link: React.ComponentType<{
+    readonly children?: React.ReactNode
+    readonly fallback?: React.ReactNode
+    readonly url: string
+  }>
   export const NoSelect: React.ComponentType<any>
   export const ScrollBox: React.ComponentType<any>
   export const Text: React.ComponentType<any>