tui: inherit Python-side rendering via gateway bridge

tui_gateway/render.py

@@ -0,0 +1,49 @@
+"""Rendering bridge — routes TUI content through Python-side renderers.
+
+When agent.rich_output exists, its functions are used. When it doesn't,
+everything returns None and the TUI falls back to its own markdown.tsx.
+"""
+
+from __future__ import annotations
+
+
+def render_message(text: str, cols: int = 80) -> str | None:
+    try:
+        from agent.rich_output import format_response
+    except ImportError:
+        return None
+
+    try:
+        return format_response(text, cols=cols)
+    except TypeError:
+        return format_response(text)
+    except Exception:
+        return None
+
+
+def render_diff(text: str, cols: int = 80) -> str | None:
+    try:
+        from agent.rich_output import render_diff as _rd
+    except ImportError:
+        return None
+
+    try:
+        return _rd(text, cols=cols)
+    except TypeError:
+        return _rd(text)
+    except Exception:
+        return None
+
+
+def make_stream_renderer(cols: int = 80):
+    try:
+        from agent.rich_output import StreamingRenderer
+    except ImportError:
+        return None
+
+    try:
+        return StreamingRenderer(cols=cols)
+    except TypeError:
+        return StreamingRenderer()
+    except Exception:
+        return None