feat(tui): use OSC 8 hyperlinks in Markdown when terminal supports them (#3248)

TerminalCapabilities already tracks hyperlinks: boolean and returns true
for Ghostty, Kitty, WezTerm, and iTerm2, but nothing generated OSC 8
sequences. This completes that stub.

Changes to packages/tui:
- terminal-image.ts: add hyperlink(text, url) and setCapabilities()
- index.ts: export hyperlink and setCapabilities
- utils.ts: extend AnsiCodeTracker to track active OSC 8 URLs
  - process() now handles OSC 8 open/close sequences
  - getActiveCodes() re-emits the OSC 8 open at each line start
  - getLineEndReset() closes the OSC 8 hyperlink before each line break
  This ensures hyperlinks wrap correctly across multiple lines.
- components/markdown.ts: link renderer uses hyperlink() when
  getCapabilities().hyperlinks is true; falls back to (url) text
- Tests: new wrap-ansi tests for OSC 8 line-wrapping; terminal-image
  tests for hyperlink(); markdown tests covering both code paths;
  table-cell width test pinned to hyperlinks:false (checks raw columns)

closes #3239

Co-authored-by: AI (Pi/Claude Sonnet 4.6) <noreply@pi.dev>
Co-authored-by: Mario Zechner <badlogicgames@gmail.com>

packages/tui/src/terminal-image.ts

@@ -81,6 +81,11 @@ export function resetCapabilitiesCache(): void {
 	cachedCapabilities = null;
 }
 
+/** Override the cached capabilities. Useful in tests to exercise both code paths. */
+export function setCapabilities(caps: TerminalCapabilities): void {
+	cachedCapabilities = caps;
+}
+
 const KITTY_PREFIX = "\x1b_G";
 const ITERM2_PREFIX = "\x1b]1337;File=";
 
@@ -372,6 +377,20 @@ export function renderImage(
 	return null;
 }
 
+/**
+ * Wrap text in an OSC 8 hyperlink sequence.
+ * The text is rendered as a clickable hyperlink in terminals that support OSC 8
+ * (Ghostty, Kitty, WezTerm, iTerm2, VSCode, and others).
+ * In terminals that do not support OSC 8, the escape sequences are ignored
+ * and only the plain text is displayed.
+ *
+ * @param text - The visible text to display
+ * @param url - The URL to link to
+ */
+export function hyperlink(text: string, url: string): string {
+	return `\x1b]8;;${url}\x1b\\${text}\x1b]8;;\x1b\\`;
+}
+
 export function imageFallback(mimeType: string, dimensions?: ImageDimensions, filename?: string): string {
 	const parts: string[] = [];
 	if (filename) parts.push(filename);