feat: convert all file inputs to FilePond for standardized uploading

- Add csv_import queue type (storeAsFile, no async upload) for CSV import dialog
- Convert file-field.php partial to FilePond with field-name→queue-type mapping
- Conditionally skip server config for storeAsFile queues in buildFilePondOptions
- Skip FilePond init for inputs inside closed <dialog> elements
- Trigger FilePond init when import dialog opens
- Load FilePond CSS/JS assets on admin index page

app/public/assets/js/app/file-upload-filepond.js

@@ -99,6 +99,18 @@
 			labelMaxFileSize: "Taille max: {filesize}",
 			allowMultiple: false,
 		},
+		csv_import: {
+			acceptedFileTypes: ["text/csv"],
+			labelFileTypeNotAllowed: "Seulement CSV",
+			fileValidateTypeLabelExpectedTypes: "CSV",
+			maxFileSize: "50MB",
+			labelMaxFileSizeExceeded: "Fichier trop volumineux",
+			labelMaxFileSize: "Taille max: {filesize}",
+			allowMultiple: false,
+			// CSV import stays as storeAsFile (no async upload to process.php),
+			// so the form submits the file directly.
+			storeAsFile: true,
+		},
 	};
 
 	// ── Helpers ───────────────────────────────────────────────────────────
@@ -300,13 +312,11 @@
 		// Per-type max size overrides (for TFE: PDF=100MB, video/audio=2GB)
 		var perExtMax = cfg.perExtensionMaxSize || {};
 
-		return {
+		// Base options shared by all queue types
+		var opts = {
 			allowMultiple: cfg.allowMultiple,
 			allowReorder: true,
 
-			// ── Async server model (replaces storeAsFile + allowProcess: false) ──
-			server: buildServerConfig(queueType),
-
 			// ── Native FilePond validation ──
 			acceptedFileTypes: cfg.acceptedFileTypes,
 			labelFileTypeNotAllowed: cfg.labelFileTypeNotAllowed,
@@ -378,6 +388,16 @@
 				if (!error) syncOrderInput(queueType, this);
 			},
 		};
+
+		// storeAsFile queues skip async upload; the file stays in the form
+		if (cfg.storeAsFile) {
+			opts.storeAsFile = true;
+			opts.allowProcess = false;
+		} else {
+			opts.server = buildServerConfig(queueType);
+		}
+
+		return opts;
 	}
 
 	// ── Public API ────────────────────────────────────────────────────────
@@ -391,6 +411,11 @@
 			// Canonical duplicate check: FilePond.find() is the authoritative source
 			if (FilePond.find(input)) return;
 
+			// Skip inputs inside closed <dialog> elements — FilePond can't render
+			// when the container has display:none. Initialize when the dialog opens.
+			var dialog = input.closest("dialog");
+			if (dialog && !dialog.open) return;
+
 			// Queue type: always from data-queue-type attribute
 			var queueType = input.dataset.queueType || null;
 			if (!queueType) return;