fix: handle non-image modalities across uploads, previews, and filenames (#255)

SnapOtter spans five modalities now, but several code paths still assumed image input.

- dropzone: default to accept-all when no fileFilter is given (image tools still pass one); neutral "supported file types" error text instead of "image files"
- automate (pipelines): accept any modality in the file pickers and dropzones; render modality-aware previews (video player, audio waveform, document/data card) instead of always using ImageViewer/BeforeAfterSlider
- filename sanitizer: extend the double-extension allowlist beyond image extensions to video/audio/document/data so e.g. "report.csv.php" becomes "report.csv"; add tests
- thumbnail route: return 422 for non-rasterisable files (audio, data, non-PDF docs) instead of attempting a doomed Sharp decode
- pool: unknown tools fall back to the "system" pool, not the image pool
- a11y labels: "Previous/Next image", "Image viewer/area/controls/drop zone" are now modality-neutral, across all 21 locales
- copy: bulk-rename default, find-duplicates ZIP name, SSRF user-agent, fetch-urls fallback name, file-details MIME label, URL-import placeholder, help dialog

apps/web/src/components/files/file-details.tsx

@@ -502,7 +502,7 @@ export function FileDetails({ mobile = false }: FileDetailsProps) {
             <DetailRow label={t.files.name} value={details.originalName} />
             <DetailRow
               label={t.files.format}
-              value={details.mimeType.replace("image/", "").toUpperCase()}
+              value={details.mimeType.split("/").pop()?.toUpperCase() ?? ""}
             />
             <DetailRow label={t.files.size} value={formatSize(details.size)} />
             <DetailRow