Add s-expression wire format support and test detail view

- HTMX beforeSwap hook intercepts text/sexp responses and renders
  them client-side via sexp.js before HTMX swaps the result in
- sexp_response() helper for returning text/sexp from route handlers
- Test detail page (/test/<nodeid>) with clickable test names
- HTMX navigation to detail returns sexp wire format (4x smaller
  than pre-rendered HTML), full page loads render server-side
- ~test-detail component with back link, outcome badge, and
  error traceback display

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

test/sexp/dashboard.sexpr

@@ -77,7 +77,15 @@
               (if (= outcome "failed") "bg-rose-50"
               (if (= outcome "skipped") "bg-sky-50"
               "bg-orange-50"))))
-    (td :class "px-3 py-2 text-sm font-mono text-stone-700 max-w-0 truncate" :title nodeid nodeid)
+    (td :class "px-3 py-2 text-sm font-mono text-stone-700 max-w-0 truncate" :title nodeid
+      (a :href (str "/test/" nodeid)
+         :hx-get (str "/test/" nodeid)
+         :hx-target "#main-panel"
+         :hx-select "#main-panel"
+         :hx-swap "outerHTML"
+         :hx-push-url "true"
+         :class "hover:underline hover:text-sky-600"
+        nodeid))
     (td :class "px-3 py-2 text-center"
       (span :class (str "inline-flex items-center rounded-full border px-2 py-0.5 text-xs font-medium "
                     (if (= outcome "passed") "border-emerald-300 bg-emerald-50 text-emerald-700"
@@ -111,3 +119,30 @@
     (div :class "text-center"
       (div :class "text-4xl mb-2" "?")
       (div :class "text-sm" "No test results yet. Click Run Tests to start."))))
+
+(defcomp ~test-detail (&key nodeid outcome duration longrepr)
+  (div :class "space-y-6 p-4"
+    (div :class "flex items-center gap-3"
+      (a :href "/"
+         :hx-get "/"
+         :hx-target "#main-panel"
+         :hx-select "#main-panel"
+         :hx-swap "outerHTML"
+         :hx-push-url "true"
+         :class "text-sky-600 hover:text-sky-800 text-sm"
+        "← Back to results")
+      (span :class (str "inline-flex items-center rounded-full border px-2 py-0.5 text-xs font-medium "
+                    (if (= outcome "passed") "border-emerald-300 bg-emerald-50 text-emerald-700"
+                    (if (= outcome "failed") "border-rose-300 bg-rose-50 text-rose-700"
+                    (if (= outcome "skipped") "border-sky-300 bg-sky-50 text-sky-700"
+                    "border-orange-300 bg-orange-50 text-orange-700"))))
+        outcome))
+    (div :class "rounded border border-stone-200 bg-white p-4 space-y-3"
+      (h2 :class "text-lg font-mono font-semibold text-stone-800 break-all" nodeid)
+      (div :class "flex gap-4 text-sm text-stone-500"
+        (span (str "Duration: " duration "s")))
+      (when longrepr
+        (div :class "mt-4"
+          (h3 :class "text-sm font-semibold text-rose-700 mb-2" "Error Output")
+          (pre :class "bg-stone-50 border border-stone-200 rounded p-3 text-xs text-stone-700 overflow-x-auto whitespace-pre-wrap"
+            longrepr))))))