fix: preserve markdown hyperlink targets

[kitlangton]

Summary

• Render concealed Markdown links as compact clickable labels only after OSC 8 hyperlink support is detected.
• Preserve a visible label (destination) fallback while hyperlink support is unavailable or unknown.
• Detect and style visible bare URLs without hyperlinking URLs inside Markdown code spans.
• Preserve distinct markup.link.label and markup.link.url styling.
• Keep generated native chunk styles isolated across live buffers while reusing stable per-buffer slots and cleaning them up on replacement/detach.
• Detect OSC 8 support in Zed and VS Code integrated terminals through the existing terminal identity path.

Before

Clickable-capable terminals displayed redundant destinations:

Check out OpenTUI (https://github.com/sst/opentui) for more.

After

When OSC 8 support is detected:

Check out OpenTUI for more.

The displayed OpenTUI label retains its label style and carries the hidden https://github.com/sst/opentui OSC 8 target.

When OSC 8 support is unavailable or not yet detected, OpenTUI preserves the visible fallback:

Check out OpenTUI (https://github.com/sst/opentui) for more.

Simplify And Safety Review

• Removed added renderer hyperlink override configuration and TypeScript FFI wiring; terminal capability detection is the single source of truth.
• Made label-only concealment capability-driven rather than adding a public rendering option.
• Removed redundant explicit Markdown-link regex scanning; parser URL ranges walk across intervening conceal highlights to associate labels.
• Kept the event-driven capability refresh path because rebuilding Markdown children during renderSelf() produces an empty transition frame.
• Limited bare-URL fallback so inline/fenced raw Markdown content is not linkified; concealed formatting delimiters are excluded from generated targets.
• Kept one-character labels clickable while preserving safety for synthetic one-character conceal replacements.
• Added support for compact titled Markdown links.
• Avoided restyling clickable label text with URL colors when label and URL theme styles differ.
• Replaced transient native style churn with stable per-buffer style slots, cleaning surplus/transitional styles on replacement/detach while preserving the TextBuffer.clear() highlight-retention contract.
• Hardened SyntaxStyle insertion rollback on allocation failure.
• Ensured OSC 8 links are opened after cursor positioning on newly rendered rows.
• Reused the canonical terminal-name path for Zed and VS Code hyperlink detection.

Verification

• bun test src/lib/detect-links.test.ts passes: 12 pass, 0 fail.
• TypeScript and Zig formatting checks pass for changed files.
• Earlier CI runs found and drove fixes for conceal-range label association and compact-link whitespace.
• The final simplify pass found and fixes single-character labels, titled links, formatted bare URLs, stable style-slot reuse, plain-text replacement cleanup, safe style insertion rollback, and OSC 8 cursor-order output.
• A rejected simplification moved capability refresh into renderSelf() and produced an empty transition frame; commit 0a9d460b restores the previously-safe event-driven refresh.
• Local renderer/native test execution is blocked by the local Zig linker failure already observed for current clean worktrees; CI builds the native library from source and is the authoritative native verification path.