feat: support multi-format — images, CSV, JSON, TXT + fix PDF embed

- PDF: <iframe> → <embed> (plus compatible webview Tauri)
- Images: .png .jpg .gif .svg .webp .bmp .ico → rendu standalone avec toolbar
- CSV: rendu en tableau HTML avec headers sticky
- JSON: affichage formaté avec indentation (html.escape)
- Texte: .txt .log .yml .yaml .py .js .sh .toml .ini → <pre> mono
- CSS: .image-viewer-body, .csv-table, .text-viewer, .json-viewer, .file-toolbar

backend/main.py

@@ -2364,6 +2364,37 @@ async def api_file(vault_name: str, path: str = Query(..., description="Relative
             logger.error(f"PDF read error for {path}: {e}")
             raise HTTPException(status_code=500, detail=f"Error reading PDF: {e!s}")
 
+    # === Images: return as viewable image ===
+    IMAGE_EXTENSIONS = {".png", ".jpg", ".jpeg", ".gif", ".svg", ".webp", ".bmp", ".ico"}
+    if ext in IMAGE_EXTENSIONS:
+        size = file_path.stat().st_size
+        mime_map = {
+            ".png": "image/png", ".jpg": "image/jpeg", ".jpeg": "image/jpeg",
+            ".gif": "image/gif", ".svg": "image/svg+xml", ".webp": "image/webp",
+            ".bmp": "image/bmp", ".ico": "image/x-icon",
+        }
+        mime = mime_map.get(ext, "application/octet-stream")
+        html = (
+            f'<div class="image-viewer">'
+            f'<img src="/api/file/{vault_name}/raw?path={path}" '
+            f'alt="{file_path.name}" style="max-width:100%;max-height:80vh;object-fit:contain" />'
+            f'</div>'
+        )
+        return {
+            "vault": vault_name,
+            "path": path,
+            "title": file_path.name,
+            "tags": [],
+            "frontmatter": {},
+            "html": html,
+            "raw_length": size,
+            "extension": ext,
+            "is_markdown": False,
+            "is_image": True,
+            "image_mime": mime,
+            "size_bytes": size,
+        }
+
     try:
         raw = file_path.read_text(encoding="utf-8", errors="replace")
     except PermissionError as e:
@@ -2388,7 +2419,57 @@ async def api_file(vault_name: str, path: str = Query(..., description="Relative
     except Exception as e:
         logger.error(f"Unexpected error reading file {path}: {e}")
         raise HTTPException(status_code=500, detail=f"Error reading file: {e!s}")
-    
+
+    # === CSV: render as HTML table ===
+    if ext == ".csv":
+        import csv, io as csv_io
+        reader = csv.reader(csv_io.StringIO(raw))
+        rows = list(reader)
+        if not rows:
+            html = "<p><em>Fichier CSV vide</em></p>"
+        else:
+            headers = rows[0]
+            data_rows = rows[1:]
+            html = '<div class="csv-table-wrapper"><table class="csv-table"><thead><tr>'
+            for h in headers:
+                html += f"<th>{h}</th>"
+            html += "</tr></thead><tbody>"
+            for row in data_rows:
+                html += "<tr>"
+                for cell in row:
+                    html += f"<td>{cell}</td>"
+                html += "</tr>"
+            html += "</tbody></table></div>"
+        return {
+            "vault": vault_name, "path": path,
+            "title": file_path.name, "tags": [], "frontmatter": {},
+            "html": html, "raw_length": len(raw), "extension": ext,
+            "is_markdown": False, "is_csv": True,
+        }
+
+    # === JSON: syntax-highlighted display ===
+    if ext == ".json":
+        import json as json_mod
+        try:
+            parsed = json_mod.loads(raw)
+            formatted = json_mod.dumps(parsed, indent=2, ensure_ascii=False)
+        except json_mod.JSONDecodeError:
+            formatted = raw
+        html = f"<pre class='json-viewer'><code>{html_mod.escape(formatted)}</code></pre>"
+        return {
+            "vault": vault_name, "path": path,
+            "title": file_path.name, "tags": [], "frontmatter": {},
+            "html": html, "raw_length": len(raw), "extension": ext,
+            "is_markdown": False, "is_json": True,
+        }
+
+    # === Plain text / other readable files ===
+    TEXT_EXTENSIONS = {".txt", ".log", ".yml", ".yaml", ".toml", ".ini", ".cfg",
+                       ".sh", ".bash", ".py", ".js", ".ts", ".html", ".css",
+                       ".xml", ".rst", ".tex", ".sql", ".conf", ".env"}
+    if ext in TEXT_EXTENSIONS or ext == ".md":
+        pass  # handled below or by markdown section
+
     if ext == ".md":
         post = parse_markdown_file(raw)