Rich output rendering: GFM markdown, tool-result blocks, card blocks

Three layers:

1. GFM markdown — add remark-gfm so tables, task lists, strikethrough,
   autolinks render properly. Style table elements (overflow-aware
   container, muted header, divider rows). Render `[ ]` task list items
   as visible checkboxes.

2. Structured tool-result rendering — new `tool-result-renderers.tsx`
   dispatches by tool name to render a small UI block beneath each
   ToolCallCard:
   - list_tenants → table with status pills + plan column
   - get_tenant → tenant detail card
   - get_platform_stats → KPI tiles (total + per-status)
   - list_audit_log → timeline rows with actor_type + action
   - list_users → user list with role chips
   - suspend_tenant / activate_tenant → tenant card with action confirm
   ToolCallCard collapses by default — operators expand for raw JSON.

3. Custom ```card``` blocks the LLM can emit inline:
   - {"kind":"pill","status":"…"} — status pill
   - {"kind":"stat","label":"…","value":…} — stat tile
   - {"kind":"callout","tone":"info|warning|danger|success",…} — callout
   Malformed blocks fall through to the prose unchanged. Client strips
   well-formed blocks from prose and renders them as components.

Domain primer updated to teach the model the card schemas and remind it
NOT to re-render tool-result data as markdown tables (that's done
automatically — it should add commentary only).

Layers are independent: 1 + 2 always work; 3 is purely additive.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

package.json

@@ -28,6 +28,7 @@
     "react-dom": "^19.2.4",
     "react-markdown": "^10.1.0",
     "react-router": "7.13.1",
+    "remark-gfm": "^4.0.1",
     "shadcn": "^4.2.0",
     "tailwind-merge": "^3.5.0",
     "topojson-client": "^3.1.0",