Create an upload

Returns a short-lived URL to upload one file directly to Tracira storage, bypassing the 4.5 MB request-body cap. Flow for large files: 1. POST /api/uploads -> `{ uploadUrl, key, contentType }` 2. PUT the raw file bytes to `uploadUrl` with header `Content-Type: <contentType>` 3. POST /api/logs with `attachments: [{ source: "uploaded", key }]` The file stages in your workspace until a log references it, then it is copied into that log. Uploads never linked to a log are deleted automatically within 24h. Accepted types: image/*, audio/*, application/pdf. Up to 32 MB per file. Each in-flight upload reserves space against your workspace storage quota (the declared `sizeBytes`, or the per-file max if omitted), so unlinked uploads can never push a workspace over its plan limit. The reservation is released when the upload is linked to a log or reaped.

curl -X POST "https://example.com/api/uploads" \  -H "Content-Type: application/json" \  -d '{}'

{  "uploadUrl": "http://example.com",  "key": "string",  "contentType": "string",  "method": "PUT",  "headers": {    "property1": "string",    "property2": "string"  },  "expiresIn": 0,  "maxBytes": 0}