Add live self-hosting bootstrapper page to bootstrappers section

- Update plan page with completion status and results
- Add ~bootstrapper-self-hosting-content component with live G0/G1 verification
- Add _self_hosting_data() helper: loads py.sx, runs it, diffs against G0
- Add "Self-Hosting (py.sx)" to bootstrappers nav and index table
- Wire /bootstrappers/self-hosting route

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

sx/sxc/pages/docs.sx

@@ -448,13 +448,25 @@
   :data (bootstrapper-data slug)
   :content (if bootstrapper-not-found
     (~spec-not-found :slug slug)
-    (if (= slug "python")
-      (~bootstrapper-py-content
-        :bootstrapper-source bootstrapper-source
-        :bootstrapped-output bootstrapped-output)
-      (~bootstrapper-js-content
-        :bootstrapper-source bootstrapper-source
-        :bootstrapped-output bootstrapped-output))))
+    (case slug
+      "self-hosting"
+        (~bootstrapper-self-hosting-content
+          :py-sx-source py-sx-source
+          :g0-output g0-output
+          :g1-output g1-output
+          :defines-matched defines-matched
+          :defines-total defines-total
+          :g0-lines g0-lines
+          :g0-bytes g0-bytes
+          :verification-status verification-status)
+      "python"
+        (~bootstrapper-py-content
+          :bootstrapper-source bootstrapper-source
+          :bootstrapped-output bootstrapped-output)
+      :else
+        (~bootstrapper-js-content
+          :bootstrapper-source bootstrapper-source
+          :bootstrapped-output bootstrapped-output))))
 
 ;; ---------------------------------------------------------------------------
 ;; Isomorphism section

sx/sxc/pages/helpers.py

@@ -230,9 +230,12 @@ def _bootstrapper_data(target: str) -> dict:
     """
     import os
 
-    if target not in ("javascript", "python"):
+    if target not in ("javascript", "python", "self-hosting"):
         return {"bootstrapper-not-found": True}
 
+    if target == "self-hosting":
+        return _self_hosting_data(ref_dir)
+
     ref_dir = os.path.join(os.path.dirname(__file__), "..", "..", "shared", "sx", "ref")
     if not os.path.isdir(ref_dir):
         ref_dir = "/app/shared/sx/ref"
@@ -276,6 +279,80 @@ def _bootstrapper_data(target: str) -> dict:
     }
 
 
+def _self_hosting_data(ref_dir: str) -> dict:
+    """Run py.sx live: load into evaluator, translate spec files, diff against G0."""
+    import os
+    from shared.sx.parser import parse_all
+    from shared.sx.types import Symbol
+    from shared.sx.evaluator import evaluate, make_env
+    from shared.sx.ref.bootstrap_py import extract_defines, compile_ref_to_py, PyEmitter
+
+    try:
+        # Read py.sx source
+        py_sx_path = os.path.join(ref_dir, "py.sx")
+        with open(py_sx_path, encoding="utf-8") as f:
+            py_sx_source = f.read()
+
+        # Load py.sx into evaluator
+        exprs = parse_all(py_sx_source)
+        env = make_env()
+        for expr in exprs:
+            evaluate(expr, env)
+
+        # Generate G0 (hand-written bootstrapper)
+        g0_output = compile_ref_to_py()
+
+        # Generate G1 (py.sx) — translate each spec file
+        sx_files = [
+            ("eval.sx", "eval"), ("forms.sx", "forms (server definition forms)"),
+            ("render.sx", "render (core)"),
+            ("adapter-html.sx", "adapter-html"), ("adapter-sx.sx", "adapter-sx"),
+            ("deps.sx", "deps (component dependency analysis)"),
+            ("signals.sx", "signals (reactive signal runtime)"),
+        ]
+        emitter = PyEmitter()
+        total = 0
+        matched = 0
+        for filename, _label in sx_files:
+            filepath = os.path.join(ref_dir, filename)
+            if not os.path.exists(filepath):
+                continue
+            with open(filepath, encoding="utf-8") as f:
+                src = f.read()
+            defines = extract_defines(src)
+            for name, expr in defines:
+                g0_stmt = emitter.emit_statement(expr)
+                g1_stmt = evaluate(
+                    [Symbol("py-statement"), [Symbol("quote"), expr], 0], env
+                )
+                total += 1
+                if g0_stmt == g1_stmt:
+                    matched += 1
+
+        g0_lines = len(g0_output.splitlines())
+        g0_bytes = len(g0_output)
+        status = "identical" if matched == total else "mismatch"
+
+    except Exception as e:
+        py_sx_source = f";; error loading py.sx: {e}"
+        g0_output = f"# error: {e}"
+        matched, total = 0, 0
+        g0_lines, g0_bytes = 0, 0
+        status = "error"
+
+    return {
+        "bootstrapper-not-found": None,
+        "py-sx-source": py_sx_source,
+        "g0-output": g0_output,
+        "g1-output": g0_output if status == "identical" else "# differs from G0",
+        "defines-matched": str(matched),
+        "defines-total": str(total),
+        "g0-lines": str(g0_lines),
+        "g0-bytes": str(g0_bytes),
+        "verification-status": status,
+    }
+
+
 def _bundle_analyzer_data() -> dict:
     """Compute per-page component bundle analysis for the sx-docs app."""
     from shared.sx.jinja_bridge import get_component_env