feat(files): add folder download as zip

- Add zip folder API endpoint
- Add download button to folder rows
- Enforce max archive size limit
- Document endpoint in OpenAPI

lib/openapi/spec.go

@@ -97,6 +97,23 @@ func Spec() map[string]any {
 					}),
 				},
 			},
+			"/api/v1/files/zip": map[string]any{
+				"get": map[string]any{
+					"summary":     "Download a directory as a zip archive",
+					"operationId": "zipFolder",
+					"description": "Zips the directory into a temporary file and streams it as an attachment.",
+					"parameters": []map[string]any{
+						{"name": "path", "in": "query", "required": true, "schema": map[string]string{"type": "string"}, "description": "Absolute path to the directory"},
+					},
+					"responses": auth(map[string]any{
+						"200": map[string]any{"description": "Zip archive", "content": map[string]any{"application/zip": map[string]any{"schema": map[string]string{"type": "string", "format": "binary"}}}},
+						"400": errResp("Invalid path or not a directory"),
+						"403": errResp("Path outside allowed root"),
+						"404": errResp("Path not found"),
+						"413": errResp("Archive exceeds size limit"),
+					}),
+				},
+			},
 			"/api/v1/download": map[string]any{
 				"get": map[string]any{
 					"summary":     "Download a file",