docs: organize tool pages by modality under /tools/<modality>/

Move all 157 tool pages into image/video/audio/pdf/data subfolders so URLs read /tools/<modality>/<id> (e.g. /tools/image/crop). Nest the image sub-categories under an Image group in the sidebar so the nav reads by modality. Add public/_redirects (301, clean + .html forms) mapping every old flat /tools/<id> URL to its new path so inbound links keep working. Rewrite all internal /tools links. Verified with a clean docs build (no dead links).

apps/docs/tools/data/create-zip.md

@@ -0,0 +1,45 @@
+---
+description: Bundle multiple files into a single ZIP archive.
+---
+
+# Create ZIP
+
+Bundle multiple files of any type into a single ZIP archive. Duplicate filenames are automatically deduplicated.
+
+## API Endpoint
+
+`POST /api/v1/tools/data/create-zip`
+
+Accepts multipart form data with two or more files. No settings field is required.
+
+## Parameters
+
+This tool has no configurable parameters. Upload 2--50 files of any type to bundle.
+
+## Example Request
+
+```bash
+curl -X POST http://localhost:1349/api/v1/tools/data/create-zip \
+  -H "Authorization: Bearer si_your-api-key" \
+  -F "file=@report.pdf" \
+  -F "file=@data.csv" \
+  -F "file=@photo.jpg"
+```
+
+## Example Response
+
+```json
+{
+  "jobId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
+  "downloadUrl": "/api/v1/download/a1b2c3d4-e5f6-7890-abcd-ef1234567890/archive.zip",
+  "originalSize": 3500000,
+  "processedSize": 2800000
+}
+```
+
+## Notes
+
+- Requires between 2 and 50 input files.
+- Any file type is accepted; there are no restrictions on input format.
+- If multiple files share the same name, they are automatically deduplicated with numeric suffixes.
+- The output archive uses standard ZIP compression (deflate).