Render research prose as Markdown with RTL tables

The analysis-and-research.md content has markdown tables (ציר דיוני)
and inline formatting like **label:** strong runs, which were
rendering as raw pipes and dashes because the compose page used
whitespace-pre-line on plain text.

Add a reusable <Markdown> component backed by react-markdown +
remark-gfm with a custom `components` map that styles paragraphs,
lists, blockquotes, strong runs, and especially GFM tables for RTL
+ aligned columns:

- table: table-auto + border-collapse, wrapped in overflow-x-auto
  so very wide tables don't push the parent card out
- th: whitespace-nowrap so the header row sets column widths and
  every row border lines up row-to-row
- everything text-right + the whole block gets dir="rtl" at the root

Use it in three places on the compose screen:
- ProseSection (represented_party, procedural_background,
  agreed_facts, disputed_facts)
- Conclusions card
- SubsectionCard field content — threshold_claims and issues have
  the same markdown shape in their fields[]

react-markdown + remark-gfm added (~30KB gzipped).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

web-ui/src/components/compose/subsection-card.tsx

@@ -4,6 +4,7 @@ import { useState } from "react";
 import { ChevronDown } from "lucide-react";
 import { ChairEditor } from "@/components/compose/chair-editor";
 import { PrecedentsSection } from "@/components/compose/precedents-section";
+import { Markdown } from "@/components/ui/markdown";
 import type { ResearchSubsection } from "@/lib/api/research";
 import type { CasePrecedent } from "@/lib/api/precedents";
 import type { PracticeArea } from "@/lib/practice-area";
@@ -76,8 +77,8 @@ export function SubsectionCard({
                   <dt className="text-[0.72rem] uppercase tracking-wider text-gold-deep font-semibold mb-1">
                     {f.label}
                   </dt>
-                  <dd className="text-sm text-ink-soft leading-relaxed whitespace-pre-line">
-                    {f.content}
+                  <dd>
+                    <Markdown content={f.content} />
                   </dd>
                 </div>
               ))}