You build the product.
Stow stores the media.

Integrate this app with the Stow media storage API. Onboard FIRST — do not write any integration code until steps 1 and 2 are done.

1. Fetch the full reference and follow it: https://www.stow-io.com/stow.txt
2. Get an API key via device pairing (the human just clicks Approve):
   - POST https://www.stow-io.com/api/pair/start (no body) -> {deviceCode, userCode, verificationUrl}
   - Open the verificationUrl in my browser for me (macOS: `open <url>`, Linux: `xdg-open <url>`, Windows: `start <url>`), and print it too in case that fails. The pairing code is pre-filled — WAIT while I log in and click Approve.
   - Poll POST https://www.stow-io.com/api/pair/claim {deviceCode} every 3s until {status:"approved", apiKey}.
   - Save apiKey to the project's gitignored .env as STOW_API_KEY. Keep it server-side only; never put it in frontend code.
3. Confirm the key works (GET https://www.stow-io.com/api/media/quota) before writing integration code.

Auth: send "X-Stow-Key: $STOW_API_KEY" on every request.

Endpoints (prefix https://www.stow-io.com):
- POST /api/media/upload-url  body {filename, sizeBytes, mimeType} -> {assetId, uploadConfig.uploadUrl}
- then PUT the raw file bytes to uploadConfig.uploadUrl (NOT to the API)
- then POST /api/media/confirm/:assetId (required, or the upload expires in ~15 min)
- GET /api/media/files -> [{assetId, filename, sizeBytes, mimeType, createdAt}]
- GET /api/media/files/:assetId/download-url -> {downloadUrl} (signed, ~10 min TTL — store assetId, never the URL)
- DELETE /api/media/files/:assetId
- GET /api/media/quota -> {tier, quotaBytes, usedBytes, ...}

Handle: 401 invalid key, 409 filename exists (no overwrites — pick a new name),
413 over quota or file too large.
Filenames: letters, digits, spaces, . _ - ( ), no slashes, no leading dot, max 128 chars.