feat(evidence): inline preview for images and text/JSON files

Adds a View button (eye icon) on each evidence card for previewable file
types. Opens a full-screen modal:
- Images (png/jpg/gif/webp/svg/…): rendered directly via <img> tag
- JSON: fetched authenticated, pretty-printed in green mono
- Text/log/md/csv/xml/yaml/…: fetched authenticated, shown in <pre>

Non-previewable files only show the Download button as before.
Modal closes on Escape or backdrop click.

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

frontend/src/api/evidence.ts

@@ -63,6 +63,21 @@ export async function getEvidence(evidenceId: string): Promise<EvidenceOut> {
   return data;
 }
 
+// ── Content fetch (for inline preview) ────────────────────────────
+
+/** Fetch raw file content for inline preview (text / JSON). */
+export async function getEvidenceRawContent(
+  evidenceId: string,
+): Promise<{ text: string; contentType: string }> {
+  const response = await client.get(`/evidence/${evidenceId}/file`, {
+    responseType: "blob",
+  });
+  const blob = response.data as Blob;
+  const text = await blob.text();
+  const contentType = (response.headers["content-type"] as string) || "";
+  return { text, contentType };
+}
+
 // ── Delete ─────────────────────────────────────────────────────────
 
 /** Delete an evidence record (only in editable states). */

frontend/src/components/EvidenceList.tsx

@@ -1,5 +1,6 @@
-import { FileIcon, Download, ExternalLink, Copy, Check } from "lucide-react";
 import { useState } from "react";
+import { FileIcon, Download, Copy, Check, Eye } from "lucide-react";
+import EvidencePreviewModal, { getPreviewType } from "./EvidencePreviewModal";
 
 interface Evidence {
   id: string;
@@ -18,16 +19,16 @@ interface EvidenceListProps {
 
 export default function EvidenceList({ evidences, onDownload }: EvidenceListProps) {
   const [copiedHash, setCopiedHash] = useState<string | null>(null);
+  const [preview, setPreview] = useState<Evidence | null>(null);
 
-  const formatDate = (dateStr: string) => {
-    return new Date(dateStr).toLocaleDateString("en-US", {
+  const formatDate = (dateStr: string) =>
+    new Date(dateStr).toLocaleDateString("en-US", {
       year: "numeric",
       month: "short",
       day: "numeric",
       hour: "2-digit",
       minute: "2-digit",
     });
-  };
 
   const copyHash = async (hash: string) => {
     await navigator.clipboard.writeText(hash);
@@ -45,8 +46,13 @@ export default function EvidenceList({ evidences, onDownload }: EvidenceListProp
   }
 
   return (
+    <>
       <div className="space-y-3">
-      {evidences.map((evidence) => (
+        {evidences.map((evidence) => {
+          const previewType = getPreviewType(evidence.file_name);
+          const canPreview = previewType !== null;
+
+          return (
             <div
               key={evidence.id}
               className="rounded-lg border border-gray-800 bg-gray-800/30 p-4 transition-colors hover:bg-gray-800/50"
@@ -63,6 +69,19 @@ export default function EvidenceList({ evidences, onDownload }: EvidenceListProp
                     </p>
                   </div>
                 </div>
+
+                {/* Action buttons */}
+                <div className="flex items-center gap-2">
+                  {canPreview && (
+                    <button
+                      onClick={() => setPreview(evidence)}
+                      className="flex items-center gap-1.5 rounded-lg border border-gray-700 bg-gray-800 px-3 py-1.5 text-sm text-gray-300 hover:border-cyan-500/50 hover:text-cyan-400 transition-colors"
+                      title="Preview"
+                    >
+                      <Eye className="h-4 w-4" />
+                      View
+                    </button>
+                  )}
                   <button
                     onClick={() => onDownload(evidence.id)}
                     className="flex items-center gap-1.5 rounded-lg border border-gray-700 bg-gray-800 px-3 py-1.5 text-sm text-gray-300 hover:border-cyan-500/50 hover:text-cyan-400 transition-colors"
@@ -71,6 +90,7 @@ export default function EvidenceList({ evidences, onDownload }: EvidenceListProp
                     Download
                   </button>
                 </div>
+              </div>
 
               {/* SHA256 Hash */}
               <div className="mt-3 flex items-center gap-2">
@@ -91,7 +111,24 @@ export default function EvidenceList({ evidences, onDownload }: EvidenceListProp
                 </button>
               </div>
             </div>
-      ))}
+          );
+        })}
       </div>
+
+      {/* Preview modal */}
+      {preview && (
+        <EvidencePreviewModal
+          evidenceId={preview.id}
+          fileName={preview.file_name}
+          previewType={getPreviewType(preview.file_name)}
+          downloadUrl={preview.download_url ?? `/api/v1/evidence/${preview.id}/file`}
+          onClose={() => setPreview(null)}
+          onDownload={() => {
+            onDownload(preview.id);
+            setPreview(null);
+          }}
+        />
+      )}
+    </>
   );
 }

frontend/src/components/EvidencePreviewModal.tsx

@@ -0,0 +1,173 @@
+/**
+ * EvidencePreviewModal
+ *
+ * Shows evidence files inline:
+ *  - Images  → <img> rendered directly (same-origin cookie sent automatically)
+ *  - JSON    → fetched via authenticated Axios, pretty-printed
+ *  - Text    → fetched via authenticated Axios, shown in <pre>
+ */
+
+import { useEffect, useState, useCallback } from "react";
+import { X, Loader2, AlertCircle, Download } from "lucide-react";
+import { getEvidenceRawContent } from "../api/evidence";
+
+// ── Helpers ────────────────────────────────────────────────────────
+
+export type PreviewType = "image" | "json" | "text" | null;
+
+const IMAGE_EXTS = new Set([
+  "png", "jpg", "jpeg", "gif", "webp", "svg", "bmp", "ico", "tiff", "tif",
+]);
+const TEXT_EXTS = new Set([
+  "txt", "log", "md", "csv", "xml", "html", "htm", "yaml", "yml",
+  "ini", "cfg", "conf", "sh", "bat", "ps1", "py", "js", "ts",
+]);
+
+export function getPreviewType(fileName: string): PreviewType {
+  const ext = fileName.split(".").pop()?.toLowerCase() ?? "";
+  if (IMAGE_EXTS.has(ext)) return "image";
+  if (ext === "json") return "json";
+  if (TEXT_EXTS.has(ext)) return "text";
+  return null;
+}
+
+// ── Component ──────────────────────────────────────────────────────
+
+interface Props {
+  evidenceId: string;
+  fileName: string;
+  previewType: PreviewType;
+  downloadUrl: string;
+  onClose: () => void;
+  onDownload: () => void;
+}
+
+export default function EvidencePreviewModal({
+  evidenceId,
+  fileName,
+  previewType,
+  downloadUrl,
+  onClose,
+  onDownload,
+}: Props) {
+  const [text, setText] = useState<string | null>(null);
+  const [loading, setLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  // Fetch text / JSON content on mount (not needed for images)
+  useEffect(() => {
+    if (previewType === "text" || previewType === "json") {
+      setLoading(true);
+      getEvidenceRawContent(evidenceId)
+        .then(({ text: raw }) => {
+          if (previewType === "json") {
+            try {
+              setText(JSON.stringify(JSON.parse(raw), null, 2));
+            } catch {
+              setText(raw); // not valid JSON — show raw
+            }
+          } else {
+            setText(raw);
+          }
+        })
+        .catch((e) => setError(e?.message ?? "Failed to load file"))
+        .finally(() => setLoading(false));
+    }
+  }, [evidenceId, previewType]);
+
+  // Close on Escape
+  const handleKey = useCallback(
+    (e: KeyboardEvent) => {
+      if (e.key === "Escape") onClose();
+    },
+    [onClose],
+  );
+  useEffect(() => {
+    document.addEventListener("keydown", handleKey);
+    return () => document.removeEventListener("keydown", handleKey);
+  }, [handleKey]);
+
+  return (
+    /* backdrop */
+    <div
+      className="fixed inset-0 z-50 flex items-center justify-center bg-black/70 p-4 backdrop-blur-sm"
+      onClick={(e) => e.target === e.currentTarget && onClose()}
+    >
+      {/* panel */}
+      <div className="flex max-h-[90vh] w-full max-w-4xl flex-col rounded-xl border border-gray-700 bg-gray-900 shadow-2xl">
+        {/* header */}
+        <div className="flex items-center justify-between border-b border-gray-800 px-5 py-3">
+          <span className="truncate text-sm font-medium text-gray-200">
+            {fileName}
+          </span>
+          <div className="flex items-center gap-2">
+            <button
+              onClick={onDownload}
+              title="Download"
+              className="flex items-center gap-1.5 rounded-lg border border-gray-700 bg-gray-800 px-3 py-1.5 text-sm text-gray-300 hover:border-cyan-500/50 hover:text-cyan-400 transition-colors"
+            >
+              <Download className="h-4 w-4" />
+              Download
+            </button>
+            <button
+              onClick={onClose}
+              className="rounded-lg p-1.5 text-gray-400 hover:bg-gray-800 hover:text-white transition-colors"
+              title="Close (Esc)"
+            >
+              <X className="h-5 w-5" />
+            </button>
+          </div>
+        </div>
+
+        {/* body */}
+        <div className="flex-1 overflow-auto p-4">
+          {/* ── IMAGE ─────────────────────────────────────── */}
+          {previewType === "image" && (
+            <div className="flex items-center justify-center">
+              <img
+                src={downloadUrl}
+                alt={fileName}
+                className="max-h-[75vh] max-w-full rounded-lg object-contain"
+                onError={(e) => {
+                  (e.currentTarget as HTMLImageElement).style.display = "none";
+                  setError("Image could not be loaded");
+                }}
+              />
+              {error && <ErrorMessage message={error} />}
+            </div>
+          )}
+
+          {/* ── TEXT / JSON ────────────────────────────────── */}
+          {(previewType === "text" || previewType === "json") && (
+            <>
+              {loading && (
+                <div className="flex items-center justify-center py-16">
+                  <Loader2 className="h-8 w-8 animate-spin text-cyan-400" />
+                </div>
+              )}
+              {error && !loading && <ErrorMessage message={error} />}
+              {text !== null && !loading && (
+                <pre
+                  className={`whitespace-pre-wrap break-words rounded-lg bg-gray-950 p-4 font-mono text-sm text-gray-300 ${
+                    previewType === "json" ? "text-emerald-300" : ""
+                  }`}
+                >
+                  {text}
+                </pre>
+              )}
+            </>
+          )}
+        </div>
+      </div>
+    </div>
+  );
+}
+
+function ErrorMessage({ message }: { message: string }) {
+  return (
+    <div className="flex flex-col items-center gap-2 py-12 text-center">
+      <AlertCircle className="h-10 w-10 text-red-400" />
+      <p className="text-sm text-red-400">{message}</p>
+    </div>
+  );
+}