Bundle analyzer: drill-down component tree with SX source viewer

Click a page row to expand its component bundle tree. Each component
shows pure/IO badge, IO refs, dep count. Click a component to expand
its full defcomp SX source. Uses <details>/<summary> for zero-JS
expand/collapse.

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

sx/sxc/pages/helpers.py

@@ -289,18 +289,34 @@ def _bundle_analyzer_data() -> dict:
         pct = round(n / total_components * 100) if total_components else 0
         savings = 100 - pct
 
-        # IO classification for components in this page
+        # IO classification + component details for this page
         pure_in_page = 0
         io_in_page = 0
         page_io_refs: set[str] = set()
-        for comp_name in needed:
+        comp_details = []
+        for comp_name in sorted(needed):
             val = env.get(comp_name)
             if isinstance(val, Component):
-                if val.is_pure:
+                is_pure = val.is_pure
+                if is_pure:
                     pure_in_page += 1
                 else:
                     io_in_page += 1
                     page_io_refs.update(val.io_refs)
+                # Reconstruct defcomp source
+                param_strs = ["&key"] + list(val.params)
+                if val.has_children:
+                    param_strs.extend(["&rest", "children"])
+                params_sx = "(" + " ".join(param_strs) + ")"
+                body_sx = serialize(val.body, pretty=True)
+                source = f"(defcomp ~{val.name} {params_sx}\n  {body_sx})"
+                comp_details.append({
+                    "name": comp_name,
+                    "is-pure": is_pure,
+                    "io-refs": sorted(val.io_refs),
+                    "deps": sorted(val.deps),
+                    "source": source,
+                })
 
         pages_data.append({
             "name": name,
@@ -312,6 +328,7 @@ def _bundle_analyzer_data() -> dict:
             "io-refs": len(page_io_refs),
             "pure-in-page": pure_in_page,
             "io-in-page": io_in_page,
+            "components": comp_details,
         })
 
     pages_data.sort(key=lambda p: p["needed"], reverse=True)