Add separate defpage for spec explorer route

The <slug> route param doesn't match slashes, so
/language/specs/explore/<slug> needs its own defpage
instead of being handled inside specs-page.

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

sx/sxc/pages/docs.sx

@@ -349,20 +349,7 @@
         "extensions" (~spec-overview-content
           :spec-title "Extensions"
           :spec-files (make-spec-files extension-spec-items))
-        :else (cond
+        :else (let ((spec (find-spec slug)))
-          (starts-with? slug "explore/")
-            (let ((spec-slug (slice slug 8 (string-length slug)))
-                  (spec (find-spec spec-slug)))
-              (if spec
-                (let ((data (spec-explorer-data
-                              (get spec "filename")
-                              (get spec "title")
-                              (get spec "desc"))))
-                  (if data
-                    (~spec-explorer-content :data data)
-                    (~spec-not-found :slug spec-slug)))
-                (~spec-not-found :slug spec-slug)))
-          :else (let ((spec (find-spec slug)))
             (if spec
               (~spec-detail-content
                 :spec-title (get spec "title")
@@ -372,6 +359,26 @@
                 :spec-prose (get spec "prose"))
               (~spec-not-found :slug slug))))))))
 
+;; ---------------------------------------------------------------------------
+;; Spec Explorer — structured interactive view of spec files
+;; ---------------------------------------------------------------------------
+
+(defpage specs-explore-page
+  :path "/language/specs/explore/<slug>"
+  :auth :public
+  :layout :sx-docs
+  :content (~sx-doc :path (str "/language/specs/explore/" slug)
+    (let ((spec (find-spec slug)))
+      (if spec
+        (let ((data (spec-explorer-data
+                      (get spec "filename")
+                      (get spec "title")
+                      (get spec "desc"))))
+          (if data
+            (~spec-explorer-content :data data)
+            (~spec-not-found :slug slug)))
+        (~spec-not-found :slug slug)))))
+
 ;; ---------------------------------------------------------------------------
 ;; Bootstrappers section
 ;; ---------------------------------------------------------------------------