Harden Fiber multipart uploads
Fiber upload helpers should enforce size limits and never persist client-controlled filenames without normalization.
#Metadata
#Why it matters
`FormFile`/`SaveFile` flows that concatenate `Filename` into paths or skip `filepath.Base` are a common path traversal and storage abuse vector.
#Remediation
Apply `filepath.Base`, cap reader sizes, allowlist extensions, and store uploads using server-generated object keys.
#Repository path
The generated metadata points to critiq-rules/libs/rules/catalog/rules/go/go.security.fiber-unsafe-multipart-upload.rule.yaml.