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.
Adds a minimal hand-rolled highlighter for ts/js/jsx/tsx, py, sh/bash, go, rust,
json, yaml, sql. Recognizes whole-line comments, single/double/backtick strings,
numbers, and per-language keyword sets. Unknown langs fall through to the current
plain rendering; the existing diff-specific colorization is preserved.
Closes the §8 "Markdown syntax highlighting is missing (only diff gets colored)"
finding from the TUI v2 audit without pulling in a highlighter library.
