feat(telegram): convert markdown tables to bullet points (#1495)

Tables render poorly in Telegram (pipes stripped, whitespace collapses).
This adds a 'tableMode' option to markdownToIR that converts tables to
nested bullet points, which render cleanly on mobile.

- Add tableMode: 'flat' | 'bullets' to MarkdownParseOptions
- Track table state during token rendering
- Render tables as bullet points with first column as row labels
- Apply bold styling to row labels for visual hierarchy
- Enable tableMode: 'bullets' for Telegram formatter

Closes #TBD

src/telegram/format.ts

@@ -51,6 +51,7 @@ export function markdownToTelegramHtml(markdown: string): string {
     linkify: true,
     headingStyle: "none",
     blockquotePrefix: "",
+    tableMode: "bullets",
   });
   return renderTelegramHtml(ir);
 }
@@ -63,6 +64,7 @@ export function markdownToTelegramChunks(
     linkify: true,
     headingStyle: "none",
     blockquotePrefix: "",
+    tableMode: "bullets",
   });
   const chunks = chunkMarkdownIR(ir, limit);
   return chunks.map((chunk) => ({