Improves transcript viewer with Markdown support

Adds Markdown rendering to the transcript viewer for enhanced formatting.

This change integrates `react-markdown` to parse and render transcript content, allowing for richer text formatting, including links and other Markdown elements.  It also adds a toggle to switch between raw and formatted text, and displays a message when transcript content is unavailable. The UI of the transcript viewer has been improved to be more user-friendly with titles and descriptions.

app/dashboard/sessions/[id]/page.tsx

@@ -0,0 +1,144 @@
+"use client";
+
+import { useEffect, useState } from "react";
+import { useParams } from "next/navigation";
+import SessionDetails from "../../../../components/SessionDetails";
+import TranscriptViewer from "../../../../components/TranscriptViewer";
+import { ChatSession } from "../../../../lib/types";
+import Link from "next/link";
+
+export default function SessionViewPage() {
+  const params = useParams();
+  const id = params?.id as string;
+  const [session, setSession] = useState<ChatSession | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => {
+    if (id) {
+      const fetchSession = async () => {
+        setLoading(true);
+        setError(null);
+        try {
+          const response = await fetch(`/api/dashboard/session/${id}`);
+          if (!response.ok) {
+            const errorData = await response.json();
+            throw new Error(
+              errorData.error ||
+                `Failed to fetch session: ${response.statusText}`
+            );
+          }
+          const data = await response.json();
+          setSession(data.session);
+        } catch (err) {
+          setError(
+            err instanceof Error ? err.message : "An unknown error occurred"
+          );
+          setSession(null);
+        } finally {
+          setLoading(false);
+        }
+      };
+      fetchSession();
+    }
+  }, [id]);
+
+  if (loading) {
+    return (
+      <div className="p-4 md:p-6 flex justify-center items-center min-h-screen">
+        <p className="text-gray-600 text-lg">Loading session details...</p>
+      </div>
+    );
+  }
+
+  if (error) {
+    return (
+      <div className="p-4 md:p-6 min-h-screen">
+        <p className="text-red-500 text-lg mb-4">Error: {error}</p>
+        <Link
+          href="/dashboard/sessions"
+          className="text-sky-600 hover:underline"
+        >
+          Back to Sessions List
+        </Link>
+      </div>
+    );
+  }
+
+  if (!session) {
+    return (
+      <div className="p-4 md:p-6 min-h-screen">
+        <p className="text-gray-600 text-lg mb-4">Session not found.</p>
+        <Link
+          href="/dashboard/sessions"
+          className="text-sky-600 hover:underline"
+        >
+          Back to Sessions List
+        </Link>
+      </div>
+    );
+  }
+
+  return (
+    <div className="min-h-screen bg-gradient-to-br from-slate-50 to-sky-100 p-4 md:p-6">
+      <div className="max-w-4xl mx-auto">
+        <div className="mb-6">
+          <Link
+            href="/dashboard/sessions"
+            className="text-sky-700 hover:text-sky-900 hover:underline flex items-center"
+          >
+            <svg
+              xmlns="http://www.w3.org/2000/svg"
+              className="h-5 w-5 mr-1"
+              viewBox="0 0 20 20"
+              fill="currentColor"
+            >
+              <path
+                fillRule="evenodd"
+                d="M12.707 5.293a1 1 0 010 1.414L9.414 10l3.293 3.293a1 1 0 01-1.414 1.414l-4-4a1 1 0 010-1.414l4-4a1 1 0 011.414 0z"
+                clipRule="evenodd"
+              />
+            </svg>
+            Back to Sessions List
+          </Link>
+        </div>
+        <h1 className="text-3xl font-bold text-gray-800 mb-6">
+          Session: {session.sessionId || session.id}
+        </h1>
+        <div className="grid grid-cols-1 gap-6">
+          <div>
+            <SessionDetails session={session} />
+          </div>
+          {session.transcriptContent &&
+          session.transcriptContent.trim() !== "" ? (
+            <div className="mt-0">
+              {" "}
+              {/* Adjusted margin, TranscriptViewer has its own top margin */}
+              <TranscriptViewer
+                transcriptContent={session.transcriptContent}
+                transcriptUrl={session.fullTranscriptUrl}
+              />
+            </div>
+          ) : (
+            <div className="bg-white p-4 rounded-lg shadow">
+              <h3 className="font-bold text-lg mb-3">Transcript</h3>
+              <p className="text-gray-600">
+                No transcript content available for this session.
+              </p>
+              {session.fullTranscriptUrl && (
+                <a
+                  href={session.fullTranscriptUrl}
+                  target="_blank"
+                  rel="noopener noreferrer"
+                  className="text-sky-600 hover:underline mt-2 inline-block"
+                >
+                  View Source Transcript URL
+                </a>
+              )}
+            </div>
+          )}
+        </div>
+      </div>
+    </div>
+  );
+}